System-of-record is DESTINATION, but no destination nid provided

I am migrating a Drupal 7 site to an updated Drupal 7 site. The nodes and taxonomies on the old site were handled in custom tables.

I have migrated 2,000 nodes and that worked fine. My taxonomy terms have also been imported. I now have a custom table of 87,000 instances of terms being applied to the nodes over seven different term reference and entity reference fields.

When I try to run the term migration I get the error: System-of-record is DESTINATION, but no destination nid provided. I have seen this error elsewhere but have not solved my problem by looking at these other issues.

This is my node migration:

class MyNodeWebMigration extends MyMigration {
    public function __construct($arguments) {
        parent::__construct($arguments);
        $this->description = t('Web Reports v2');

        $query = Database::getConnection('default', 'datasource')
            ->select('my_data_group', 'sdg');
        $query->fields('sdg', array('groupid', 'name', 'description', 'notes', 'grp_level',
            'level1', 'level2', 'submitted', 'published', 'approver_notes', 'preprocessed',
            'themeid', 'public_health_significance', 'target_event', 'talking_points',
            'report_type', 'nid'));

        $count_query = Database::getConnection('default', 'datasource')
            ->select('my_data_group', 'sdg');
        $count_query->addExpression('COUNT(groupid)', 'cnt');

        $this->source = new MigrateSourceSQL($query, array(), NULL,
            array('map_joinable' => FALSE));

        // Set up our destination - nodes of type web_ready
        $this->destination = new MigrateDestinationNode('web_ready');

        $this->map = new MigrateSQLMap($this->machineName,
            array(
                'groupid' => array(
                    'type' => 'int',
                    'not null' => TRUE,
                    'description' => 'Report Group ID.',
                    'alias' => 'sdg',
                )
            ),
            MigrateDestinationNode::getKeySchema()
        );

        // Mapped fields
        $this->addFieldMapping('title', 'name')
            ->description(t('Mapping Report name in source to node title'));
        $this->addFieldMapping('status', 'published');
        $this->addFieldMapping('field_group_id', 'groupid');
        $this->addFieldMapping('body', 'description');
    }
}

This is the second migration I am using to import the terms into the fields on my nodes:

class MyReportTypeTermToWebMigration extends CMyMigration {
    public function __construct($arguments) {
        parent::__construct($arguments);
        $this->description = t('Imports Report Type Terms Into Web Reports');

        $query = Database::getConnection('default', 'datasource')
            ->select('my_data_meta', 'sdm');
        $query->fields('sdm', array('groupid', 'vocab', 'tid'))
            ->condition('vocab', 'report_doc_type');

        $count_query = Database::getConnection('default', 'datasource')
            ->select('my_data_meta', 'sdm');
        $count_query->addExpression('COUNT(groupid)', 'cnt');

        $this->source = new MigrateSourceSQL($query, array(), NULL,
            array('map_joinable' => FALSE));

        $this->systemOfRecord = Migration::DESTINATION;

        // Set up our destination - nodes of type web_ready
        $this->destination = new MigrateDestinationNode('web_ready');

        $this->map = new MigrateSQLMap($this->machineName,
            array(
                'groupid' => array(
                    'type' => 'int',
                    'not null' => TRUE,
                    'description' => 'Report Group ID.',
                    'alias' => 'sdg',
                )
            ),
            MigrateDestinationNode::getKeySchema()
        );

        // Mapped fields
        $this->addFieldMapping('nid', 'groupID')
            ->sourceMigration('CBHSQNodeWebReady');
        $this->addFieldMapping('field_report_doc_type', 'tid')
            ->separator(',')
            // Note this is the machine name of the user migration.
            ->sourceMigration('CBHSQTermReportDocType');

    }
}

When I run this second migration I get the error in the title of this issue. Any help would be greatly appreciated.