Volume levels changing in aux channels

Hey guys. We use a gld80 at church. Recently there has been an odd issue. We use 7 auxs for our iems. When we set the volume for individual instruments in each so that everybody’s mix is good, at times, different things will drop in volume in any given persons ears. I double checked the setting and all channels are set to pre fader. Anyone have this issue? Allen and heath said they had no clue.

Only thing I can think of is if someone is changing the gain for those inputs.

Sorry, that’s probably not much help. Hope you figure it out!

this would involve a lot of speculation
this could be everything

and I think it’s not an issue with the console

Could there be a group or two being sent to the aux mixes? The group would change with the main mix, so that could cause such an issue.

Thanks guys. I thought possibly that one sound guy may have been messing with gains, but it happened to my wife as well who knows her stuff. It’s really weird because routing and everything is normal. Now, it’s never happened to me personally, but I have been around when it does.