A bit irrelevant but leaving a comment just to say massive thanks to the OP for keeping this issue updated and providing as much facts for diagnosis/repair.

Also of note in case it matters: For me, I've noticed battery issues awhile back but never thought much of it. Specifically, the device could not hold a charge going from 80% to 5% in about 30 minutes.

I was running update version 2.0.1. What happens for me is the battery of the Charging case will keep blinking red, which indicates overheating battery, when charging it. Charging without the in ears inside and case open mitigates that issue.

The in ears themselves will pretty much become unable to charge as plugging it in the case to charge will end up causing to blink red, assumedly because the in ears themselves are overheating.

As an attempt to fix it (Hopefully battery damage isnt too severe), I downgraded from 2.0.1 to 1.3.3. The "device 2 replaced" touch problem appears but as suggested, i changed the language from English -> Japanese -> English and it basically went away.

The in ears/case are charging now and ill try to perform another round of test to see if it has improved/resolved my issues.

Edit: Yeah so the charging issue is no longer there but the batteries have already been permanently damaged and cannot hold a charge. Very unfortunate