We have a relationship between say Incident and Contact. However, we have placed contact lookup on the form in two different sections. If you use dev tools to find out the ID of these two fields, you see them as new_contact1 and new_contact2. The relationship name is new_contact.
The issue is when you click on the lookup text and then click anywhere on the form, it gives a lookup error that No records found. Click to create a new record. However, the lookup is already filled. There is no unsaved change either.