I noticed this when I checked the connection after weird things happened. I have a green bar, the enemy has green bar, but my melee doesn't deal damage nonetheless. Or I would get shot through walls, etc. Then, when I looked 1 minute later, suddenly a lot of red/yellow bars are in the game, which changed to green soon after. Repeat endlessly. Back then, I would have thought about lag switchers or MTU manipulation, however this theory nowadays supposes the existence of 3 lag switchers in any given match I play. That's simply unrealistic.

It doesn't matter if you have the best connection in the world when you match people on another continent.

bad internet or not if someone in your game is lagging it can cause the whole lobby to lag.