Phantom/Bugged Entities created by spawners

[MissPotato]

Modpack Version

1.2.1

Describe your issue.

Under unknown circumstances entities can unload in a way that they become bugged. These entities are not seen by /forge entity list, /execute, /tp, /data, and the ctrl+u menu. Not even going into peaceful gets rid of them. Computer Craft Turtles can't see them. Though pressure plates will give off redstone as if being stepped on, Mob Detector from Industrial Foregoing does the same. Construction Wands will not build in the occupied spaces as if an entity was in the way. Spawners of the same type of mob will have it count against their spawn cap. The player is able to place and break blocks in the position of the glitched entities.

As of right now I've only gotten it to reproduce with wither skeletons. Vindicators and Blazes have been fine. It isn't directly related to them dying as in one setup the bugged entities weren't in the range of the turtle. I also tried killing them using pedestals and it still happened. It doesn't seem to be a chunk border issue either, as the spawner setup is all set up inside a single chunk. I don't think it's the agitator as it also happened with the Elder Eye upgrade though they could both use the same method.

Not sure if related but it could be that these entities prevent their chunk from unloading, as the Ctrl+u chunk map the chunk with the bugged entities as "loaded but not ticking" even after waiting half an hour. Though there are other random chunks like this.

https://i.imgur.com/Yraplif.png (Image of 4 spawners only able to spawn 1 skeleton.) https://i.imgur.com/JrWcejv.png (Image showing location of glitched entities, places where the wand refused to place blocks.) https://pastebin.com/J6dXbDMC (Spawner data for the new setup with only two spawners where it happened again.)

Attached is the latest.log, for some reason everything from before I joined is missing. However this was after a server reboot. Given that the chunks are not being unloaded, I assume they broken mobs are not even written to the region file.

I have some theories:

1. An enchant is preventing a mob from unloading fully.
2. Withers Skellies specifically are having issues being unloaded.
3. Spawners with modifications from Dungeon Crawl cause unloading issues.

Crash Report

No response

Latest Log

https://gist.github.com/MissPotato/f8080ba7bd57fdbc0e178bbc7773b669

Have you modified the modpack?

Yes

User Modifications

Enabled chunk loading through FTB Chunks and increased the activate range of Dread Lamps.

Did the issue happen in singleplayer or on a server?

Server

[NielsPilgaard]

Thank you for the report, we will investigate the issue.