I’ve experienced audio sync issues when using 4 corner adjustment. I’m using Picopix Max with JBL Charge 3 bluetooth speaker and it works perfectly when I don’t have the 4 corner correction on, but when I do, I start getting small framerate issues on video playback and the audio goes off sync.
One thing to note is, that this only happens when I play video from my MicroSD-card. Netflix and YouTube both work well even with 4 corner adjustment on.
The MicroSD in question is a Kingston Canvas GO! Plus (Class 10, UHS-I, U3, V90, A2) and I’m playing 1080p video from it. It works perfectly without the 4 corner correction.