@galakanokis and @idolfun have reported an issue where certain files being output have one or more frames out of order at near the beginning of the file. In the case I saw, frame 27 in the output file looks like it comes from a frame in the source file before the mark in - i.e. it shouldn’t have been output at all.
Upon re-outputting the material, the problem disappears. There is some suspicion that the problem is more likely to occur when the systems are busy.
The source material in this case is RED EPIC 5K.
We’ll look into how this could happen. If anyone else sees anything like this, please update this topic with any other info you might have.