Whenever someone hosts a LAN Server through the ESCAPE Menu in a Singleplayer world. With him alone being in it cause no tick rate problems.

When one or more users connect to the server in addition to the host via direct LAN or VPN LAN *The hostile mob spawn rates stop, thus no hostile mobs spawn, plants stop growing, leaves stop decaying, hunger does not fall nor heal or any other automatic block updates. Monster spawners work. * This occurs the moment a second user joins or after a few minutes of them joining.

(The issue sometimes is forced when the users are far away from eachother's loaded chunks in addition to time after a second user joins.)

Personal attempts to fix it:

We attempted to try and change difficulty settings, tick rates, spawn rates, spawn radius, render distances, chunk loads, user numbers, chunk updates, world generations, buffets, limited spawn spots, killing all entities in a zone and changing hosts. None worked.

Worked solutions:

• Changing and hosting in Minecraft Java Edition version 1.13.2.