I know that the gamma bug exists and the current way to fix this is by hitting escape a few times.

1 map that’s causing this bug a lot more than the other maps is Refinery. It felt like I had to fix it after every other round.

Possible cause:
I think it may have to do with shadows. I had my shadows set at ‘Medium’, when I had set it to ‘Low’, it seems like this bug was happening more often.
For clarity I was still getting the gamma bug with medium shadows, but not as often.