I'm not using the user relations at all.
I'm just having relations between post custom terms and custom post types. Which I assume is the reason for the behavior.
So I have custom taxonomy which I added to "Posts". Since I need the same taxonomy all over different Custom Post Types, I made a relation between them. Example:
'id' => 'events_to_units',
'from' => array(
'object_type' => 'term',
'taxonomy' => 'units'
'to' => array(
'post_type' => 'events',
'meta_box' => array(
'title' => 'Add Unit'
Now there is a select "Event" Relation Meta box below each post. But I never added a relation between post and CPT.
Hope that helps to understand my issue.