I have noticed that sometimes when I am scrolling through rigs using the rig left or right button a certain patch will completely max out the gain. If I go forward or back using the rig buttons to another profile, then come back the gain goes to normal status. It is intermittent, but it has happened quite a lot (specifically when I have renamed rigs to store under my own names so they are prepended with GA <rig_name>.
It's pretty whacky, but at least I know I can move away and then come back to the rig and the GAIN drops to normal.
