Don’t know what zombified means. When I solo a bunch of tracks and hit the blinking red solo button at the top of the screen, Ardour crashes. I can’t save. All I can do is “just quit” and start again. JACK shows no errors or anything.
So I’m just going to have to hit each track’s solo button individually, which is a pain, but at least Ardour doesn’t crash that way. Version 3.5.
“Crashing” is a term that most of us use for a program ceasing to run any more. What you are describing is “zombification” which is where a JACK client (such as Ardour) fails to complete its audio processsing in a timely fashion and is evicted by JACK from any further processing. What period size do you use with JACK?