using carpet-tis v1.9.1
crash log: crash-2020-11-27_19.18.51-server.txt or https://paste.ee/p/VVUPu

crashes upon joining a world. however, it doesn't crash with carpet v1.4.18

fabric-carpet v1.4.19 changed the signature of method canUseCommand which causes the crash

fixed in 1.9.2, check the release page

1.9.2 works with latest carpet for me