I'm playing on a self hosted server with the modpack All of Fabric which contains Identity.
After using the Ghast abilities, the server crashed and we got the following crash report: Paste.ee link.

We also saw that the GUI was completely broken:

Are you able to reproduce the same crash with the NotEnoughCrashes mod? If so, could you send the resulting crash report? The deobfuscated stack trace may help.

It's ok Jamie, I have a tool for mapping the log, but thanks for asking. Will look into this tonight.

I have narrowed down the conflict here. #26

Going to assume these issues were fixed from dep updates in 1.5 (as #26, with same issues, was fixed due to them). Let me know if the Ghast issues still persist.