I will look for the root cause of the bug. There was a bunch of video clips on A1 and A2 with video filters on them.
The bug occurs when there is a video on A1 but no video on V1 and the tracks were added in a certain order (video, audio, video, …). Workarounds include (assuming you want to use the audio of the video clip):
- move the video on an upper video track to V1
- move the video clip on A1 to A2
- on the video clip on A1, in Properties > Video set Track to None
Here is the minimal project that reproduces it. It should show white in the top right corner with blue underneath.
bug20343.mlt (7.4 KB)