Minecraft spectator mode

Hello I am not sure if this is intended or not but in minecraft snapshot 14w25a i went into spectator mode to see if when i took the pov of a guardian the shader would change, however when i did so all guardians disappeared. I then went back into creative mode and saw that none of them had despawned so spawned in a couple of spiders an went back into gamemode 3 and again I was not able to see the spiders I then noticed that only peaceful mobs were visible yet I still couldn't take the pov of them.