When I added the PairAdjustment through the code editor and clicked OK, all the PairAdjustments I had worked on disappeared. I tried to reproduce them. Adding or editing through the code editor causes PairAdjustment disappear. Thank you.
Confirmed. The bug will be fixed asap.
This update should solve the issue:
https://www.high-logic.com/tmp/fontcreator/FontCreatorSetup15.0.0.2988-x64.exe
Let us know your results.
It worked. Thank you!