I tried to spawn some mobs (item frames and pillagers) and none of them appeared. I can hear the pillagers making their sounds but I see nothing. I can place item frames, it makes the sound of placing it and I hear the sound when I click on the block that the frame is on, but I can break the block without having to break anything else first (if that makes sense). Yes, I have reloaded chunks and the game and still no solution. It randomly stopped showing all mobs, even mobs spawned in from before. After I break the block behind the item frame, the break sound happens a few seconds after and then an item drop follows of the frame.

I would provide pictures but you wouldn't see anything if I did!