When enabling cinematic camera mode in a single player world, move your head around and then pause the game. Your head will pause in it's last position but doing this in a multiplayer server or realm server, this will cause your player's head to stop moving but it should not because it is a multiplayer world. The player's head should keep moving.

How to reproduce

1. Go into a realm or multiplayer server.
2. Enable cinematic camera mode
3. Move your player's head around really fast.
4. Pause the game.