One or more Prismatic Cobwebs will collapse when removing negative enchantments on an anvil minecraft

If you have a crash you will need to provide a crash report. You can reopen this issue if/when you provide one.

Anvils: 64 or more Prismatic Cobweb: When removing an enchantment book negative enchantment, it crashes, does not respond, and cannot provide a crash report

I think you have another mod causing this bug. The prismatic cobweb does not even offer any behavior when in the left slot. It only works in the right slot (ref: here)

3 mods

Even 3 mods can't handle this bug