Mobs do not appear naturally in any way and nowhere, neither hostile nor passive, this has been happening a lot with this copy of the world in the realm, we use some add-ons but they do not harm this at all, apart from what was mentioned there are also errors such as delays in the sky, food It is not consumed, the blocks are not removed, there is delay between players and lag in general.
Hi! Thank you for report!
As you are saying it's occurring mostly on your world. Can i please for attachment with any needed add-ons/behavior packs, data packs, resource pack and world file. Clearly. Everything that is loaded to your realm to allow me verify your world and combination of addons. If Addons are downloaded from marketplace - please describe them with name of the addon and author of the add-on.
Issue will re-open after response