I just got (or noticed) the same issue. Video/audio lag with both the youtube app, netflix and browser youtube. HBO just doesn't work, but HBO downtime is quite common so not sure if hbo's issues are related.
Video freezes for a sec or two, then the video and audio is out of sync.
I have not updated to one ui yet (waiting for them to fix the animation lag first)
Checked my sony xz2c, no problems there. What is going on?
Edit: A restart seems to have fixed it, we'll see how long it lasts tho.