I have a mainstage setup on my MBP running the latest OS and latest version of mainstage.
My setup is basically a series of songs inside each of which I have about one or 2 different instruments that I switch between in various parts of the song. For example a piano from Kontakt for a verse, then switch to a synth by Arturia for the chorus etc.
After a little while some of these instruments will just stop outputting sound. Levels are still being shown inside the plugin but no sound gets to the output.
It seems to be the same thing discussed in this old archived thread:
The only way to get the sound back is to restart mainstage or reinstantiate my channel strip settings. Panic button does not bring the sound back. Also does not seem to be related to the "expression" setting as some suggested in the old thread.
It does not happen to all patches and does seem to be happening to the same ones over and over. I cant find anything unique about the settings for the ones that are dropping out versus the ones that are not. No idea what is triggering it.
Needless to say this means big problems for what this software was made for, live performance.