Mob Spawning

I don't know if this happens in all platforms of the game but could someone fix a bug where mobs keep spawning entering the portal and killing players also another bug about creepers spawning in front of a player every twice a day it's really getting annoying and I end up losing alll must stuff !! PLEASE FIX THIS ITS GETTING ME MAD. I know its just a game but Thank You.

Actually even better, I was testing this out in survival digging a bunch of obsidian in the caves like a stack or less, it happens to any mob all the time behind you. Test this out see for yourself if you can.