Export broken - black frames inserted

Glg Posts: 1


I'm using HF Express 2021.03.

When I export videos, there are black frames inserted in a regular pattern. Audio is not in sync.

This happens now with older projects, that used to export ok.

Footage is 50 fps, project is set to 50 fps, export is set to 50 fps.

If I set export to 25 fps, no black frames inserted. But of course motion is not smooth at all any more.

Reinstalled, cleared caches, rebooted, all the usual things without any effect

Any advice?

Thanks, Martin