All Mobs Freeze

I was hosting an LAN game for one other person. I Walked out of my house to find a bunch of Pillagers had spawned in the middle of the village. They were all frozen one of them in mid air which makes me think they had just spawned. every other mob (villagers, iron golem, lamas, horse) was also frozen. by frozen I mean they didn't move or make any sound. They couldn't be pushed or hit either. I was still able to move and open and shut doors. The other player was kicked out of the game entirely. When I tried to quit, the game began 'saving' interminably.  eventually I force quit. When I reloaded I had gone back in time 5-10 min.