Not sure how your mapping is made..By T do you have that making in to out? If so, that is unnecessary for a match frame….won’t affect what your problem is, but just saying….
You should be able to do exactly what you are saying. Only turn on the V1 or V2 track for the item you want to match frame…hit match frame, and you are good to go.
What options are you given if you try to cut what you’ve match framed back into your sequence? Is there a video track available on your source side? Is it possible the viewer icon on your source side is turned off?
(Little square next to the V1 track)
Try right clicking on your clip and accessing match frame this clip from there. See if it does anything different.
Glenn