Singleplayer
Minecraft 1.12.2 Forge2705
TheBetweenlands-3.3.10-universal

Hi here! I've crashed tonight and while reading the lines, I guess I could reproduce the bug.

How to reproduce

I was in the betweenlands, and I was listening to a music disc. I don't think which one matter, but it was the frosty chrismas one. Then I've jump onto a portal and as I was about to deal some stuff in the overworld. Then after... xsec the game's crash. It look like if the game have crash at the sec the music disc would have finish playing it there still was a player around to listen to it. But since I'm in singleplayer and I was in an another dimension, I was too far away to be able to ear the song.

Installed mods:

May take a while but :
XaerosWorldMap_1.2.5_Forge_1.12
VillagerTrades-1.12-0.6.4 + borntobe-1.12.2-1.0
*Here what you are looking at
Hwyla-1.8.26-B41_1.12.2
WailaHarvestability-mc1.12-1.1.12
Wawla-1.12.2-2.5.257
AppleCore-mc1.12.2-3.1.3
*Shadows-of-fire
FastWorkbench-1.12.2-1.5.1
Magical+Map-1.12.2-3.1.0
Placebo-1.12.2-1.4.0
Plants-1.12.2-2.9.2
natura-1.12.2-4.3.2.42 + Mantle-1.12-1.3.2.24
InGame-Info-XML-Mod-1.12.2 + Stackie-Mod-1.12.2 + LunatriusCore-1.12.2
*Just Ennough items
jei_1.12.2-4.11.0.202
blockdrops-1.12.2-1.4.0
jeivillagers-1.12-1.0.2
jeiintegration_1.12.2-1.5.1.36
JustEnoughResources-1.12.2-0.8.7.41
JEROreIntegration-1.12.2-1.1.0
*Insane96
carbonado-1.4.7-mc1.12.x + galaxite-1.0.6-mc1.12.x
nethergoldore-1.1.2-mc1.12.x + vulcanite-1.3.10-mc1.12.x
*Giacomos
GiacomosBookshelf-1.12.2-1.2 + GiacomosMaps-1.12.2-1.2.3 + GiacomosTravelogue-1.12.2-1.0.6
Corail+recycler-3.0.0-1.12 + tombstone-2.10.0-1.12
BlayTheNinth+CraftingTweaks_1.12.2-8.1.9 + Waystones_1.12.2-4.0.49
BiomesOPlenty-1.12.2-7.0.1.2393-universal
Baubles-1.12-1.5.2 +rustic-1.0.6
AromaBackup-1.12.2-2.1.1.3.b103 + Aroma1997Core-1.12.2-2.0.0.0.b155
5-The 5zig Mod v3.12.5 for Minecraft 1.12.2
*+ a bunch of others...
WrapUp-1.12.2
world_generation_profiler-[1.8-1.12.2]-1.2.1.5
WearableBackpacks-1.12.2-3.1.3

VanillaFix-1.0.9-97 + JustEnoughIDs-1.0.0-6 or this one?

unloader-1.2.0 Note that this one may be involved

SimpleSponge-1.12.2-3.6.1
Reliquary-1.12.2-1.3.4.763
RealBench-1.12.2-1.3.3
NaturesCompass-1.12.2-1.5.1
moreloottables-1.12.0-0.1.0
Lucky-Block-Mod-1.12
keywizard-1.12.2-1.5.3-b1
justthetips-1.12-1.0.1.1
foamfix-0.9.9.1-1.12.2-anarchy
FastLeafDecay-Mod-1.12.1
Exotic+Birds+1.12.2-1.4.1
easiervillagertrading-1.12-forge14.21.1.2387-1.2
CoralReef-2.5-1.12.2
BetterFps-1.4.8
Bedrock+Miner+1.12.2+by+XxRexRaptorxX+(v.1.0.3)

Link to full crash log

Link and latestlog provided
https://paste.dimdev.org/uhutakoful.mccrash
latest.log

Let me know If you need more information, I'l be glad to help!

Oh and before I submit, could I suggest the following to reduce cpu usage?
A) Like could you reduce the amount of loaded entities who are allowed to update themselves? When I'm 100 feet underground, when I use my world map I could see all the anglers who play their light animations and their patrol movements, I could count poodle layer when it rain and sludge path when I pass under a sludge plain... nothing of this is useful to keep updating, as I won't notice them since I'm that far away anyway!! ?
B) Moss. As example, moss reproduce itself way too fast both underground and over it, after a heavy rain or around rotten barks. Note also that moss is not the only block who try to grow in a entire chunk at any height or distance from a player : thorn, lichen, (note hanger doesn't seems to grow fast so they are fine.)
C) Chunks stay loaded for way too long. Ex On a mob's looting trips, If I die 1200 block away from my re-spawn point, 1h later, I could see that a good amount of chunks around my re-spawn point have stayed loaded since my crops have grown!
D) Mobs path finding search me like if they can see through wall! When I'm deep underground, a possessed swamp hag could target my characters even when I'm more than 12 blocks away, and swamp hag are able to regroup, to use strategy in a cavern as soon as 1 of them have me on sight. Often I'l end up in a 6 vs 1 fight, whit a reinforcement of 4 on the lose; where they jump cliffs just to reach me... Not a complain its kinda fun and challenging, but also creepee to see how far they could detect and search a path through pitstone and betweenstone!! (almost like if there where leaves.) Fun fact, when I try to cover behind a wall made of weedwood planks, The planks actually work as cover against a possessed swamp hag, as I won't receive any additional missile attack from the wight; from a much shorter range.
E) when passing though a well lighted underground, Swamp hag position are saved for later?... that make me think ... how many of them there is in a single chunk when I load one and or how many mobs move toward my position when They try to surround me? Would it be easier for a cpu to spawn mobs closer around the player and congeal the others one for a later use?
Note : I have a old intel laptop so that explain why I worry that much, I hope... I have lots of fun and enjoy playing this mod... Thk for the hard work!

Oh! I got a minor issue this time :
https://paste.dimdev.org/nefivejife.mccrash

A NullPointerException because I was feeding an already tamed Harlequin toad, to see if this could heal his wounds. It does, but this action also caused this issue. (Dragonfly wings).

Same common environment info than last time.

Hey! Thanks for reporting this, I'll try to reproduce it.
Regarding your other remarks:
A) That's not something we plan on doing and there might already exist a mod that does that (maybe check out the mod Tick Dynamic?). Alternatively you can limit the maximum number of entities in the Betweenlands config.
B) Moss works pretty much the same way as Thorns, Lichen etc. which grow in any loaded chunk. However, your suggestion of making them only grow near players is something I'll consider adding.
C) That's not really under our control, we're not keeping the chunks loaded after a death. Maybe you died at the world spawn point that keeps the area loaded, which is a vanilla mechanic.
D) That's just how it is :)
E) Yes, they are saved, but they despawn after a while like vanilla's hostile mobs. Regarding the spawning area, I can make a config to specify the maxiumum and minimum distance where mobs can spawn.

Oh! I got a minor issue this time :
https://paste.dimdev.org/nefivejife.mccrash

Will be fixed in the next update. Already fixed in dev.

TODO:

• Make Moss, Thorns, Lichen etc. only grow near players. Config option?
• Config option for min/max mob spawn distance from player

Oh and for future reference, if you run into multiple different bugs please create a seperate an issue for each, makes it easier for us to organize 👍

Wow that was fast, thk a lots and yes I will try to make separate issue. Thk for your answer about my suggestion too ^^ Should I close the issue?