Game has started hanging after saving on quit to main screen

[WebDragon]

Modpack

FTB Plexiglass Mountain

Modpack version

1.2.4

Log Files

https://pste.ch/ulakufetoh Debug.log https://pste.ch/terexocoya latest.log

Describe the bug

on quitting, it takes an inordinately long time to exit out to the main screen (the one you see first after launching the game completes) from the current instance.

this only started happening recently, so I'm curious what might be the problem and how i could go about resolving it

Steps to reproduce

1. played for about 60 days, explore a lot in the overworld, the nether, and the end, do some mining in the mining dimension with mekanism,
2. eventually as I go to quit, it starts hanging and requires me to force-stop the running java instance in the Task Manager in order to fully exit, and it doesn't matter how long I wait
3. scratch head in puzzlement

Expected behaviour

normal quit to main screen after saving

Screenshots

No response

Additional information

it's apparently saving successfully since I have not had any world corruption yet, so I don't know what might be the problem. Otherwise the game is playing fine and I'm having no other issues.