mobs spawn in random places in my base

After saving the game and then joining again mobs from my farms are spawning in random places inside my base, including villagers from a closed farm who end up on the roof where there's no access to it. sheep that I located in a wool farm somehow are back in the minecarts in which they were before moving (minecarts that I destroyed and shouldn't be there).

Killing them doesn't change anything as they respawn straight after joining the realm again, so as replacing the game with a backup. 

Also what is worth to mention this bug doesn't affect my builds. Everything is exactly as I left it, just mobs are all over the place. Downloading a copy of realm and playing locally makes no difference.