In a different situations with longtime running game server mobs just won't naturally spawns at world (Overworld/Nether/End).
It's can be fixed only with server restart, but not for long time - spawn rate brokes again when some count of players will connect to game, play some time and disconnect.
Steps to reproduce:
Run multiplayer game;
Play some time with other players;
Do a disconnect from server;
...
Here's an example from my dragon battle game (in russian, but it's not important). There's no any hostile mobs (and Endermans) was spawned during a gameplay (excl. Ender Dragon)
Gameplay on YouTube - http://www.youtube.com/watch?v=QoXbCUA4nRk
Related issues
Comments
[Mojang] Mega_Spud (Jay)
migrated
Thank you for your report!
We're actually already tracking this issue at MCPE-21856, so we will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature, to see if the issue has already been mentioned.
Quick Links:
📓 Issue Guidelines – 💬 Mojang Support – 📧 Suggestions – 📖 Minecraft Wiki