Error occurs when using Fabric Carpet "stackableShulkerBoxes" rule, which allows empty shulker boxes to stack to 64.

Logs: https://pastebin.com/uf8HkzZF
Screenshots: https://imgur.com/a/DphgfS8
Client: Fabric, 1.16.5

Additional:
I also received infinity loop error with the same inventory yesterday, however am not able to replicate the issue again.