I'm having the same issue since the CoreELEC update to 8.99, based on LE9. Everything has been working fine before, now multiple keys don't work anymore, like STOP and EPG, for my custom configured remote on a Amlogic S905 box. Getting the same non-functional error logs for those keys, though libinput shows that they're mapped just fine.
Sepp: Have you found a solution yet?