PDOEcxeption when creating an ECK entity

Using
Drupal 7.54
ECK 7.x-2.0-rc9

I created an entity type and bundle. When adding a new entity of that bundle I get a WSOD:

PDOException: SQLSTATE[23000]: Integrity constraint violation: 1048 Column 'entity_type' cannot be null: INSERT INTO {entity_modified} (entity_type, entity_id, modified) VALUES (:db_insert_placeholder_0, :db_insert_placeholder_1, :db_insert_placeholder_2); Array ( [:db_insert_placeholder_0] => [:db_insert_placeholder_1] => [:db_insert_placeholder_2] => 1503601376 ) in entity_modified_entity_update() (line 50 of (...)/entity_modified/entity_modified.module).