>>332833361
Muscle memory combined with game mechanic abuse.
With high ping especially what you see them doing isn't 1:1 what they're seeing or doing. They may have seen you far longer than you see them, they may have fired 3 shots at you for every 1 you saw, they may have actually stopped for longer but the movement animations blended together on your end. The netcode is a mess and good players know how to use it to their advantage or limit the chance that it will be used against them.