Lots of good info but one thing left out - the bitness versions of Office. Perhaps where you got the form from was one version and the current project is something else? I would be surprised to learn that would do it, but who knows? Or maybe you're on a different version with the current project (e.g. you worked on it at home and took it to work and they're not compatible).
P.S. your profile details say other than Access 2019?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.