“Sync data to/from device” is already on, for both.
FF’s documents say it does sync binders when it’s on.
Okay, so if Sync is On on both devices then, in theory, the Binders should be in sync. So while you're waiting to hear from FF Support, I'd try the following:
- On both devices go to the More Menu > Account and Sign Out (at the bottom of the page)
- Close FF and any other Apps you have open
- Check for iPadOS updates and any App updates
- Shutdown both devices NOTE: The devices take 30+ seconds to shut down, it's not just when the screen goes black. So WAIT a bit.
- Turn both devices back on, and again pause a bit for the WiFi to connect
- Open FF and Sign In on both devices. Wait 30 sec or so and then go delete a Binder and the Recreate the Binder
- Wait a bit and then go check on the other Device
* If there happen to be any FF Database updates pending, do those too, then go check to see if the Binders came over to the new device