problem with mobs

since yesterday i've been having this issue. When i enter a sever  with perfect ping i have problems with mobs, they don't move for me, or spawn invisible and any birds flap wing, but stay stuck on the ground and suddenly disappear. I have removed any mods i had and the server has barely any mods also before these 2 days i could play fine with no issues. I contacted the admins of the server and they said it was on my end because no one else in the server had this issue. I've tried uninstalling the game and reinstalling it but it still has the same issues. PS: this is on the beta version