I had two iron golems in my village that I spawned in snapshot 15w35e. They were totally normal and had never even attacked anything in my village. The village had several houses (and doors that I added to breed villagers). The next time i get onto my server after the game version updates I spawn in my home to find that the iron golems have turned hostile, are attacking me when i never touched them and never harmed a villager, killing all of my snow golems, and worst of all, attacking my villagers! The server admin had to come help kill them off and the whole episode was extremely upsetting.