Cannot move upon joining.

Upon joining certain servers, my character is unable to move as well as currently on-screen mobs. Their animations will still play, however you/they cannot move from Point A to Point B. If you've "attempted" to move whilst encountering this bug, upon relogging you and all other mobs will appear at Point B. I've verified integrity of game files, disabled all mods, and I have a good connection to the server. Other people on the server are able to play the game fine, so this must be a client-side issue.