Possible Fixes

Yes

Modpack Version

1.14

What happened?

I've had my dedicated server crash twice now and it seems to have happened users have used spells from the Iron's Spellbooks mod to kill mobs.

Crash Log

https://gist.github.com/1337phreak/5fe4f3ee95254b2ff72dcc026e1a6392

Latest.Log

https://gist.github.com/1337phreak/324ddc918f02024b4c1e5ae8f8d56e32

I'm also having this same issue, I'm noticing that the crash is happening when i cast a spell on an infernal mob . if need to ill share my crash log as well.

I do believe for my server crashes the mob being attacked was augmented by the Infernal Mobs mod as well.

I also had this happen though it was just a common Drowned... though it did have a backpack and some buffs. I had used poison arrow if that matters.

I am running a ATM10 server Ver 1.14. We are also seeing server crashes whenever anyone uses a Iron's Spellbooks spell to damage any mob.
I've attached our latest log for people to verify, However this is happening in SP as well.
https://gist.github.com/Microjett/f726e48e193426d92bfa23971eb5d605

Test in SP:
I loaded up a SP world in creative mode grabbed a irons spellbook spell scroll and fired it at some nearby cows and as soon as they took damage the game crashed.

This appears to be happening for any Irons spell that causes damage to another entity.
Also as far as I know eating the lollypop item can also cause random Iron's spells to happen and therefore crash the sever if those effects manages to damage another entity

Edit - Note: I just ran a test using just the Iron's Spells and Spellbooks mod and its dependencies in a neoforge client (21.1.73) and was able to use spells with no crashing at all.

the newest update has fixed this issue for me