Hostile mobs are not spawning in the overworld.

We're on a multiplayer server. So many of us have spent all of our time since the update in the Nether that few have noticed the mob spawning issues in the overworld, but yesterday. myself and another player went to kill some creepers and maybe start a raid at a little one room "village" we created. Nothing spawned through several day/night cycles. Not a single hostile mob. Even when standing on the roof of the building, in the middle of a dark plains, nothing spawned. We're on hard mode so things should have spawned. I did hear a single hostile mob underground and too close to me to despawn. Other than that...nothing. 

Today the same player went out to see if it was just a glitch, something weird. Nope. No hostile mobs spawned, however he was able to get Pillagers to spawn at their tower where last night we didn't even get that. 

We're on the latest version and have are playing with sim6

I'll try to record a video clip to upload to this report.