Copied app behaving differently to original

With the type ahead search feature, the behavior is different...in a good way. Yes, the differences will cause some issues and they can be fixed pretty easily. For example, in your case, the columns that are being shown when you click on the dropdown arrow needs to be rearranged to make sure the value you are showing on the screen appears first. Without type-ahead search, this order does not affect how the value of the field appears. But with type-ahead search, the column whose value you choose to show on the form must appear first. Let me give you an example:

Let us just say you have a dept table and an employee table. If you choose to show the dept name instead of department record id# on the related department field, in edit mode, it would show the department name, while the actual value of that field is a number. This is before type-ahead search. But after type-ahead search, even in edit mode, it will show the number, if the number and the name appears in the dropdown list, in that order. If you change the order of these fields, to department name followed by record id, then in edit mode, it will show the department name. As for why the form rules behave differently in the old vs the copy, I would need to see those rules and the field names etc. QuickBase support may be able to help you with that. I am not sure if it has anything to do with type-ahead search,