1.20.1 Server Crash using Mediafy Item with non-stackable items/motes

[starji]

Encountered a server crash on the 1.20.1 hexcasting test modpack using Mediafy Item. When an item is attempting to be mediafied into a Mote Nexus, an optional mote parameter may be provided to automatically mediafy the item into the mote, however if the items cannot be stacked, this causes a crash in the 1.20.1 branch. e.g. Attempting to mediafy a stack of gravel into a mote containing dirt. This occurs on a multiplayer server and in single player.

I did also check the 1.19 versions, however this only resulted in a mishap; no crash.

crash-2024-05-04_18.17.59-server.txt
crash-2024-05-04_18.37.47-server.txt

[Twisted-Code]

Why do I so often see unhandled mishaps? I presume they are supposed to be caught by the interpreter, so how do they slip by if all ops run under the interpreter?
(I'm trying to recall other examples, maybe they can be helpful here as more cases in point of what you might be doing wrong)