How to reproduce

• Use a mutual reference between a single content metadata (A) which is not in a repeater and a single content metadata (B) in a repeater.
• Create a content (C1) and set the value of A to another content (C2).
• Save C1 and open the other content C2 in visualisation. It will show a repeater entry with metadata B that reference C1.
• Re-open C1 in edition and save without doing anything.
• Re-open C2 in visualisation. A new repeater entry has been created to reference C1 but it should not because a similar entry was already existing.