Surface Pro 4. Survival world. Never used Creative on this one. After exiting Minecraft, and logging back in - mobs which had been in captivity for real-world months suddenly all escaped at the same time. No enclosures were broken. Villagers escaped En Masse from a surrounding glass enclosure. Glass all still in place. Pigs, Chickens and Cows all escaped from 2 x deep pits that had fences around the top. All pits still in place. "Hundreds" + of each type of mob are now running around my base. Especially in places that should not be possible. Like cows up on platforms up in the air. The cows somehow climbed ladders also, and ended up in an otherwise completely enclosed room (only entrance was the ladder). Now full of cows. I realize this is going to be hard to reproduce, plus hard to believe given that this could have all been staged, however I assure you this is legit.