Can go through random mobs

Randomly during a multiplayer game i would find a mob that is operating normally, but then when I try to hit the mob it does not take any damage. I am also able to go straight through the mob (as shown in the screenshots below) . Sometimes, a trade button will appear when i am near the mob, yet the mob shouldn't be able to trade and pressing the trade button does nothing. The only circumstance in which I have observed this is during a multiplayer game where one person is on a apple ipad and another on a samsung galaxy tab, where we are near a village, and the glitched mob is a sheep.