See https://www.curseforge.com/minecraft/mc-mods/spartan-weaponry/issues/295 for more info.
Both this and the original version cause this issue.

Can't reproduce and looks like a mixin compat error, try installing latest mixinbooter

Fixed. Curse page never mentions MixinBooter anywhere.

It is in dependency page the whole time, but I guess I better to put it in description