Relogging on a server in 15w31c makes entities dissapear that then reappear after another relog

Relogging on a server in 15w31c makes entites like villagers and iron golems dissapear completly, they aren't just invisible, f3 doesn't show that there are any entities at all where there were some prior to the relog, the villagers/iron golems appear back after a second relog