Formats duplicated in D6 upgrade

I have a Drupal 6 site that I want to migrate to Drupal 8. Both D6 and D8, and the additional D8 contrib modules for migrate are at the latest versions. I can import / migrate all the nodes but: the body field for every node is empty.

I have followed the instructions here: https://www.drupal.org/upgrade/migrate which involves using this module. I'm running the migrations using drush.

I've set up the reference to the drupal 6 database to be migrated as discussed here: https://www.drupal.org/node/2551147

drush migrate-upgrade --configure-only runs fine.

I run drush migrate-import --all and successfully import a lot of content (including 800+ users), and as said, the titles for all the nodes are there but the body field for every node is empty.

How do I fix this? Not sure which module I should raise an issue against? Is there a way of editing / inspecting the migrations that migrate-upgrade creates?

Output from drush migrate-import --all

Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'block_content_type'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'contact_category'
Processed 3 items (3 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_date_formats'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_dblog_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_file_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_search_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_statistics_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_cron'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_date'
Processed 1 item (0 created, 0 updated, 0 failed, 1 ignored) - done     [status]
with 'd6_system_file'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_image'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_image_gd'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_logging'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_maintenance'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_performance'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_rss'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_system_site'
Processed 2982 items (2982 created, 0 updated, 0 failed, 0 ignored) -   [status]
done with 'd6_url_alias'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_user_mail'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_user_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'menu_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'search_page'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'taxonomy_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'text_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'update_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'block_content_body_field'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_contact_settings'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'menu'
Missing filter plugin: filter_null.                                      [error]
Missing filter plugin: filter_null.                                      [error]
Missing filter plugin: filter_null.                                      [error]
Processed 3 items (3 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_filter_format'
Processed 3 items (3 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_custom_block'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_user_role'
Processed 60 items (18 created, 0 updated, 0 failed, 42 ignored) -      [status]
done with 'd6_block'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_comment_type'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_comment_field'
Processed 6 items (6 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node_type'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_comment_field_instance'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_comment_entity_display'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_comment_entity_form_display'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_comment_entity_form_display_subject'
Processed 11 items (6 created, 0 updated, 0 failed, 5 ignored) - done   [status]
with 'd6_field'
Processed 13 items (8 created, 0 updated, 0 failed, 5 ignored) - done   [status]
with 'd6_field_instance'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_view_modes'
Processed 64 items (40 created, 0 updated, 24 failed, 0 ignored) -      [status]
done with 'd6_field_formatter_settings'
Processed 13 items (8 created, 0 updated, 0 failed, 5 ignored) - done   [status]
with 'd6_field_instance_widget_settings'
Processed 479 items (0 created, 0 updated, 479 failed, 0 ignored) -     [status]
done with 'd6_file'
Processed 32 items (32 created, 0 updated, 0 failed, 0 ignored) -       [status]
done with 'd6_menu_links'
Processed 0 items (0 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_user_picture_file'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'user_picture_field'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'user_picture_field_instance'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'user_picture_entity_display'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'user_picture_entity_form_display'
Processed 830 items (830 created, 0 updated, 0 failed, 0 ignored) -     [status]
done with 'd6_user'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_node_settings'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_upload_field'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_upload_field_instance'
Processed 1819 items (1819 created, 0 updated, 0 failed, 0 ignored) -   [status]
done with 'd6_node__article'
Processed 45 items (45 created, 0 updated, 0 failed, 0 ignored) -       [status]
done with 'd6_node__event'
Processed 21 items (21 created, 0 updated, 0 failed, 0 ignored) -       [status]
done with 'd6_node__page'
Processed 2951 items (2951 created, 0 updated, 0 failed, 0 ignored) -   [status]
done with 'd6_node__recording_data'
Migration failed with source plugin exception: SQLSTATE[42S22]:          [error]
Column not found: 1054 Unknown column
'field_recordingdata_' in 'where clause': SELECT
0 AS delta
FROM 
{content_type_recording_file} t
WHERE  (field_recordingdata_ IS NOT NULL ) AND (nid =
:db_condition_placeholder_0) AND (vid = :db_condition_placeholder_1);
Array
(
    [:db_condition_placeholder_0] => 977
    [:db_condition_placeholder_1] => 7915
)

Processed 2 items (2 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node__recording_file'
Processed 2 items (2 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node__webform'
Processed 4 items (4 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node_revision__article'
Processed 2 items (2 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node_revision__event'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node_revision__page'
Processed 148 items (148 created, 0 updated, 0 failed, 0 ignored) -     [status]
done with 'd6_node_revision__recording_data'
Migration d6_node_revision__recording_file did not meet the              [error]
requirements. Missing migrations d6_node__recording_file.
requirements: d6_node__recording_file.
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_node_revision__recording_file'
Processed 1 item (1 created, 0 updated, 0 failed, 0 ignored) - done     [status]
with 'd6_node_revision__webform'
Processed 6 items (6 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node_setting_promote'
Processed 6 items (6 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node_setting_status'
Processed 6 items (6 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_node_setting_sticky'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'user_profile_field'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'user_profile_field_instance'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'user_profile_entity_display'
Processed 7 items (7 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'user_profile_entity_form_display'
Processed 830 items (830 created, 0 updated, 0 failed, 0 ignored) -     [status]
done with 'd6_profile_values'
Processed 3 items (3 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_taxonomy_vocabulary'
Processed 28 items (28 created, 0 updated, 0 failed, 0 ignored) -       [status]
done with 'd6_taxonomy_term'
Processed 3 items (3 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_vocabulary_field'
Processed 4 items (4 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_vocabulary_field_instance'
Processed 4 items (4 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_vocabulary_entity_display'
Processed 4 items (4 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_vocabulary_entity_form_display'
Migration d6_term_node__1 did not meet the requirements. Missing         [error]
migrations d6_node__recording_file. requirements:
d6_node__recording_file.
Migration d6_term_node__2 did not meet the requirements. Missing         [error]
migrations d6_node__recording_file. requirements:
d6_node__recording_file.
Migration d6_term_node__3 did not meet the requirements. Missing         [error]
migrations d6_node__recording_file. requirements:
d6_node__recording_file.
Migration d6_term_node_revision__1 did not meet the requirements.        [error]
Missing migrations d6_node__recording_file, d6_term_node__1,
d6_term_node__2, d6_term_node__3, d6_node_revision__recording_file.
requirements: d6_node__recording_file. requirements: d6_term_node__1.
requirements: d6_term_node__2. requirements: d6_term_node__3.
requirements: d6_node_revision__recording_file.
Migration d6_term_node_revision__2 did not meet the requirements.        [error]
Missing migrations d6_node__recording_file, d6_term_node__1,
d6_term_node__2, d6_term_node__3, d6_node_revision__recording_file.
requirements: d6_node__recording_file. requirements: d6_term_node__1.
requirements: d6_term_node__2. requirements: d6_term_node__3.
requirements: d6_node_revision__recording_file.
Migration d6_term_node_revision__3 did not meet the requirements.        [error]
Missing migrations d6_node__recording_file, d6_term_node__1,
d6_term_node__2, d6_term_node__3, d6_node_revision__recording_file.
requirements: d6_node__recording_file. requirements: d6_term_node__1.
requirements: d6_term_node__2. requirements: d6_term_node__3.
requirements: d6_node_revision__recording_file.
Migration d6_upload did not meet the requirements. Missing migrations    [error]
d6_node__recording_file. requirements: d6_node__recording_file.
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_term_node__1'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_term_node__2'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_term_node__3'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_term_node_revision__1'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_term_node_revision__2'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_term_node_revision__3'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_upload'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_upload_entity_display'
Processed 5 items (5 created, 0 updated, 0 failed, 0 ignored) - done    [status]
with 'd6_upload_entity_form_display'
Processed 830 items (830 created, 0 updated, 0 failed, 0 ignored) -     [status]
done with 'd6_user_contact_settings'

I was expecting errors on the recordings_data and recordings_file nodes as there is a lot of custom code and configuration in D6 on that, but for standard pages and stories, I'm puzzled why the body content is missing?