solo stopped working

5.1.1

Opened an older session (created in N 5.1.1) the other day and solo didn’t work. Every time I solod some tracks no audio would playback from the solo’d track. Has to choose “No Bus” and then reselect the destination bus, and then disable and reenable solo for solo to work. Had to do this with several tracks from the session. Then later on as I was working this issue would occur again and again on other tracks and sometimes on the same tracks I already fixed.

I’ve also seen group tracks that are impossible to delete. I even delete them from VST connections and they do not go away.

I would guess its some sort of session corruption.

Anyone ever see this before?