I have had FMPA crash on me a number of times when exiting from field definitions. In today's case, it occurred after adding a new text field. In all cases, it happens very shortly after clicking OK to save/exit the Manage Database window, and in all cases my changes do get saved to the remotely hosted database.
FMPA 15 with FMS 13.
I am sending a crash dump log back-channel to TSGal.