output midi channel changing randomly?

Hello folks

Anyone know of a bug where suddenly every channel is routed to midi channel 12? Or something like that?
I was just working on something in my large Hollywood Orchestra template and suddenly everything sounded very wrong!
I checked the outputs in Cubase and although everything was still routed to the correct PLAY instance, everything was being routed to channel 12 within those instances.
Is this a bug or have I just accidentally pressed something?

Thanks

Hmm! This has just happened again!
Suddenly all my tracks were changed to midi channel 16.
And if I try to change a tracks midi channel back to what it should be, changing one track changes the midi channels of all tracks!
What am I accidentally pressing for this to happen!?

Any help welcome!

Happens seemingly randomly to me, from time to time…has done so for many years, with many versions of Cubase.

A project which was sounding fine last time it was saved, when loaded up again, some MIDI tracks have apparently changed MIDI channel - like a ghost in the machine. Usually affects tracks routed to Halionsonic, but it was occasionally doing it to other multi-timbral VSTs (certainly Hypersonic) before Halionsonic was released.

The symptom for me often seem to be that a core drum part (kick, hi-hat, snare) gets routed to a channel with a piano or string sound…easy to fix, just put the channel number right again in the inspector and re-save.

I know how wacky and un-repeatable this appears, and had reluctantly filed this matter in my head under ‘seems like a bug, but probably down to poor typing skills / hitting a key inadvertently’. But what key would it likely be?