Just another charming quirk, nothing to see here. 

It'll only take me another 15 minutes to get them right again. No biggie. Hell stuff like this is almost therapeutic isn't it. 

I'm pretty sure this is likely not the problem, but just in case...

The Quick Grouping thing is wonderful except for the few times when it's sandbagged me because I still had my finger on the ctrl key and adjusted something, or I thought I was doing ctrl-something and ended up quick grouping something on all channels instead.

As I said, I doubt this is what's happening in your case, but as it has happened to me maybe it has happened to you.

Offset mode?

Offset mode and Quick Grouping have caught me by surprise a few times too - and I have experienced a couple of questionable moments wrt this too. One time I felt like Jamesyoyo did in his thread.

But usually, it's QG and/or Offset mode combined with butterfingers...


Yeah, therapeutic.... 

I call mine sausage fingers, but it's the same effect

Sausage fingers? Butter fingers? Whatever they are when my head doesn't communicate with them properly. Of course I blame the fingers. My head is always in ship shape! At least I have to blame something I can actually see 

Four thumbs and a big toe on each hand...

Hmm don't think it's offset mode, I'm always aware when that's on. For the record, and I'm not concluding that this had anything to do with it, but I noticed it right after I'd been deleting unused synths from the rack. Last time I did that, my project experienced all kinds of crashes and weirdness and I had to abandon it, this time I was carefully saving before and after deleting each synth and everything seemed OK but right after I noticed that everything sounded wrong reverb wise. It was then I noticed all sends were set to 0. Hopefully this is one of those one-off things and it doesn't happen again....send knobs, I've got my eye on ye. 

Perhaps a MIDI file with Volume events at the start?