When I try to export captions as a sidecar SRT file the subtitle track gets turned off and doesn't work in Media Encoder. If I Export directly the sequence directly it usually works, but I always have to turn the subtitle track back on.
I finally got around to testing this. I did not get to it until after I upgraded to 22.0.0 Build 25.
Let me first add that I had difficulty getting to the Export screen. Ctrl-M and File -> Export -> Media did nothing. Then I clicked on the "Export" option at the top left. The export space opened, but "no sequence" (or something) selected. For each of those tests, I clicked on the timeline to be sure I was in the sequence. But after that, Ctrl-M etc all worked.
The first time I got the sequence to export window, Captions was turned on, with burned in set. I changed it to sidecar/srt. I exported directly through PR successfully. I immediately went back to the sequence, and the Caption Track was disabled (eyebal visibiility off). And of course, when I went to export, Captions were off and could not be turned on.
I repeated, and I could see, behind the export progress window that the captions in the sequence were disabled. And when the export completed, the captions were indeed off. The export was okay.
So I confirm this bug. I did not test via AME. I did not test sidecars other than srt. I tested with a project with one sequence and one caption track. I wonder what happens with multiple sequences and tracks per sequence.