Thank you for your post!
I have been unable to reproduce similar behavior with Global Fields in FileMaker Go 15 on iOS 9 or iOS 10 between different generations of iPads and iPhones using a local file I copied to each device.
-Have you tried running Recover on one of these files?
-Would it be possible to get a sample with instructions to reproduce?
Yes, I can imagine that it is hard to reproduce. Was so surprised myself.
But certainly you have better ways to look into the files, so I will provide you with one or two of the samples on a private channel. It contains customer data and I do not want to change too much to not cover the possible reason for the behaviour.
And yes, I did recover one. Found it working after the recovery the way described on the desktop.
Send me a message and I'll send you the files backchannel