This is prolific on Realms and is breaking so much of the game. I have old cave systems which are now spawning monsters again, affecting rates of mob farms and endangering villagers, etc. Also all of my 'safe' places (i.e. base, storage, etc.) and constantly infested. It's making the game very tedious to play since I have to light everything up multiple times per day. This is SUPER important to fix soon, please.
I've been kicked from Realms going both ways through nether portals and it happens around 40-50% of the time.
On Realms all of my villagers in my iron farm just disappeared within about an hour. Iron farms need beds so I was curious whether this is related to the other bug that villagers can access beds without a valid path (i.e. through walls) or if the villagers were getting out of bed in the morning and clipping through walls. Please fix SOON as this breaks so much of the game.
UPDATE: Since my villagers disappeared not long after a raid I decided to test this in my test world and sure enough, after I successfully defeated a raid I just managed to catch my last villager despawning (with that white puff of smoke).
I suspect the end of a raid has something to do with villagers disappearing but I don't know why. Either way, this makes Iron Farms horrendously vulnerable to raids...