Pressing "esc" doesn't pause the game

If you press "esc" to pause minecraft it doesn't actually pause it. It looks like its paused but if you come back to it after any time and go back to game it does everything it would have done without pausing.
This includes:
Time circle (time circles till it's at the time it would be without pausing)
Mobs move rapidly (make every move they'd have done without pausing)