Registration App relationships edit section does not allow editions and deletions

Registration App relationships edit section seems to only work as expected when adding new relationships.

Delete isn't working: When editing, the user is allowed to delete an existing relationship. The changes are visible in the frontend and seem ok but, after saving the form and reloading the edit section, we see that nothing has happened on the server. Previously deleted entry still remains on the list.

Update isn't working: If the user changes an existing entry on the relationships edit section. Again, everything seems fine on the frontend but, after saving the form and reloading, previously modified entry remains with old values and, a new entry was created with the new values. We end up with a new created entry instead an updated old one.

It seems that the server is iterating the submitted list by the frontend and, if an exact matching entity already exists on the database, nothing is done, otherwise a new entity is created.