i have / had the same problen, I went into To the TV setup and adjusted the audio bar a few milliseconds .
I guess we should turn in a ticket to AVOV. I've owned 6 AVOV boxes "GREAT SUPPORT"
My other AVOV + doesn't have the audio delayI think its on the other end, not a problem with the boxes.
same here nothing like that its your kodi setting and what kodi are you using
then that not box its them most of time or your just to slow on internet