I'm having almost the same issue. The audio is out of sync as soon as I start a show/streaming. Rewinding the show a few seconds will fix the issue. It only does this on my Streambar Pro. It works fine if I play Hulu directly through my TCL Roku TV.
I tired all of the trouble shooting options you suggested and it still has the issue.
I am also getting jittery video on other channels when using the Streambar OS. But works fine directly from TV
