Massive bug found (?) with relationships between posts and users!!!!

This is my use-case:

A “student” (user) buys a “course” (custom post type) and upon purchase, a relationship is created between the user and the post. This is what grants the user access to the course content.

All has been working wonderfully. Until today.

A course was removed from ALL users who had a relationship with that course! This was NOT supposed to happen.

This happened immediately after I deleted a single user.

Upon further investigation I found that coincidentally the user who was deleted had the exact same ID as the course that went missing for all other users that had a relationship with it.

Upon deleting that particular user, it deleted all rows in the mb_relationships table which pointed to that post/course with the same ID.

To be clear, I deleted a user with the ID of 154 and then any reference in the mb_relationships table to a course with an ID of 154 was removed.

Here is the method in my plugin code which creates the relationship.

protected function register_relationship_for_user_tutorial_access() {

    \MB_Relationships_API::register([
        'id'   => 'the1914_user_to_tutorial',
        'from' => [
            'object_type' => 'user',
            'meta_box'    => [
                'title' => 'Tutorials',
            ]
        ],
        'to' => [
            'object_type' => 'post',
            'post_type'   => 'tutorial',
            'meta_box'    => [
                'title' => 'Students',
            ],
            'query_args' => [
                  'post_parent' => 0,   // Show ony parent tutorials
                  'number' => 100       // Maximum to show in the admin area
            ]
        ],
        'reciprocal' => true // Prevent metabox showing in the 'to' (tutorial) post type
    ]);

}

Is this an oversight from the developers of this plugin?

Or is this expected behaviour based on my code above?

I have since set ‘reciprical’ to FALSE in case that had something to do with it. That does not solve this issue.

Furthermore, when I access the profile of a user to add or remove courses, if the user ID matches a course ID, I get a LOT of dropdown menus appear like this:

Image

Here is a screenshot of the mb_relationships table:

Image

Thank you for your assistance and for an otherwise great set of plugins!