Everytime i pvp on a world/realm the movement is very weird.

I was playing my pvp world with some friends and we noticed that everytime we would try to hit each other multiple times which is called a combo, and everytime we would try to follow up on the first hit something would stop us from doing a combo on each other.

Steps to reproduce

1.Get a player or mob
2. Try to combo them

Expected results: something blokcing u from comboing
observed results: something is blocking me from comboing.
please fix this its really hard to pvp on worlds and realms. I have looked at other reports of this and its been going on since febuary?