It's happened to me a couple of times, usually while editing/recording automation on a completely unrelated track. When I reported it before, someone said I must be pressing the CTRL key and that this is causing a group edit. Since then, I've been very careful not to do that and it has still happened. Definitely a bug, but I can't recreate it at will.
Like you, I've become very careful of saving after a
good edit, and closing the project without saving when I see weird stuff like this. I've also setup a "canary" audio track that I can check that has no FX or PC enabled. When it lights up, I know something has gone wrong.
To reiterate, the ProChannel becomes enabled, and a single band of EQ in the Quad Curve goes all the way up or all the way down, on
every track.
Regards,
Dan