Thank you for the reply and knowledge around this. Your diagnosis was spot on. I do indeed have another app on my iPhone that has apparently "claimed" this UTI. I have confirmed this by deleting the app which then allows me to import the GPX file just fine. I have applied the changes as you have recommended but the other app still seems to "override" my app. Any suggestions on how to overcome this challenge?

I have tried this UTI but doesn't seem to resolve the issue. As a "work around", I have decided to remove the custom file type definition letting the user select any file type. If they select anything other than GPX, I display an alert letting the user know that only GPX file types are supported. Thanks again for the recommendations but figured if Apple can't fix this then I won't be using it.