Also posted to carpet team: #515. Please check the link for more details.

Hmm you might be using a slightly outdated version of ConfiguredKeepInventory. The crash that is happening is related to me accidently leaving a feature that conflicts with how carpet outputs its command stacktrace. I'll release a new jar without this change if you have the latest version (1.1.1).

Wait never mind I saw your mods list. It's a problem on my end will fix soon

Ok i've submitted it to curseforge just get the latest release there. Tell me if it works or if it still crashes again.

Tried it out, works. Thanks for fixing.