Guns do zero damage after a while

I play one match without issues, then when I join the second match of the day all my guns stop doing damage. AR's do no damage, sniper rifles do no damage, pistols do no damage. Grenades do no damage either, I could throw one into a middle of five enemies but not one of them takes any damage from it. The recon motion sensor ball doesn't always ping enemies who stand right next to it. It's like I'm in ghost mode except I take damage normally. I don't know about vehicles but it doesn't affect Blasco's stick, Paiks wallhack or Irish turret, those work just fine.

This has been happening since the latest big update. Only "fix" I've found is to force-quit the game and relaunch it. I have no latency issues, no lag, ping is low. It doesn't happen when the servers are having trouble, either. It always starts after the game has been running for 20 - 40 minutes. After relaunch it doesn't happen again on that session, no matter if I continued to play for the next two or three hours. I only play "official" modes, never in Portal or against bots so idk does it affect those as well. I've lost count for how many times I've emptied an full AR mag into an enemy's back, only for them to turn around and kill me with two shots.

Steam is the platform. I have almost 800 hours in this game and this is the first time I've encountered this bug. I've had ping close to 50 and while it was laggy at times (40 now) I still did damage to players. I post this more as an bug report than asking for help to fix it, because I can't find an "proper" channel for posting bug reports.