I've been experimenting with the Stormyx Carmot Staff, and it seems to crash whenever any arrow collides with it. First crash was from a pillager, second one I tried with a skeleton, but the game crashed even before it nocked an arrow, which leads me to believe it was the arrow entity on the ground.

Fireballs were being deflected without issue, also.

crash-2024-09-25_23.31.53-client.txt

crash-2024-09-25_23.21.38-client.txt

Considering this is a client crash, I suspect there being some mod compat going on here. I am not able to reproduce the second crash, which seems related to particles.
I have found one potential issues with arrows, which should be fixed as of the commit above

For some reason Inventory Tabs seems to be crashing here. Do these still happen if you disable that mod?

Yes, I've tried it without now. However the game did not crash this time, as Neruina prevented it whilst calling it a Ticking Entity Exception.

Edit: found informations in the log below
latest.log
I've also found out it happens with splash potions from witches, and that wind charges and the musket balls from the musket mod interact as intended with it.

This is now released as 0.20.2. Could you try out this version and see if you still experience crashes?

I've tested it, works fine with modded and vanilla projectiles now, thanks for the help!