I still can’t work out how to completely reproduce the bug.
I believe it might have something to do with the order of applying filters
The issue occurs about 50% of the time for me if I add fade ins and fade outs to the image that I split after I have split it and added a transition. 80% if its a video.
I am not entirely sure what I am doing to cause the bug.
Each time I repeated it, the video was always chroma-keyed.
Hopefully, somebody can do some more investigating to try to reproduce the bug.
Oh also, I found a workaround.
If you put the track where the fade out should start, then create a transition between the two then remove the section where you want the fade out to go, you can apply the fade-out to the transition and it will work as expected