[Information]

Minecraft version: 1.16.1
Forge version: 32.0.69
Environment: Singleplayer & Multiplayer

[Mods]

Mod name: Just Player Heads
Mod version: 1.16-1.1

Mod name: Just Mob Heads
Mod version: 1.16-3.4

Description

Crash after successive world generation.
Most likely it happened because of forge update to 32.0.67 - new update for events registration.
The same (if it is really same) issue was also in Mekanism, Refined Storage, Immersive Engineering, Curios, etc.

Crash report

crash-2020-07-18_02.47.58-server.txt
debug.log
latest.log

Well, sorry for duplicate)

Thanks for letting me know and using the mods! I've released an update for every mod which uses commands. It was indeed the forge update which caused the issue.