I tried both your options but unfortunately they didn’t work.
What helped me a bit was extending the duration of the movie component from 1 sec (video duration) to 1.2 secs. This resolved audio issues.
I’m currently updating a new version with different attempts (https://run.pavlovia.org/f.cerpelloni/sequential/html).
The probable cause of the issue is refresh rate. The video is composed of a fixation point and a gabor that flashes (1 frame duration) either left or right. In the missed trials, the fixation point is still displayed, the audio works, but the flash is skipped.
Also, errors are not consistentin which movie is skipped