Nether Spawn in Normal World

My partner and I started a Realm recently to be able to play on our own without the interference from others, a day or so after we start playing the game starts acting weird and randomly teleports us on top of a tall structure near our base. Which intially wasn't a big deal, until it started spawning Blazes, Ghasts, and Ravagers with no riders, and witches on top of said structure as well as livestock like horses and chickens. Only a few minutes ago it spawned the wither above our base as well. Knowing enough about Minecraft I figured it had to be some sort of bug as we haven't even been to the nether yet. To go into more detail, while I'm on top of the Mob Farm Structure which is around 40 blocks or so from the ground where we are located, witches, ravagers, chickens, blazes etc will fall from the sky onto the structure.  Please look into the issue (On a side note, at night it seems more entities spawn than normal. As instead of a few zombies, we're getting 5 or 6 showing up. A multitude of skeletons etc. All within a 40 block radius from our base if not closer)