See Earthcomputer/clientcommands#396

This should be fixed on our end like #10

Ideally no one should assume stability of this name and should just try catch it anyway. Throug official api for that would be also good idea

Yeah, this isn't going to be possible for us to fix.

It's not a matter of a simple class/field not found -- it takes the fabric_currentPage field in the transformed jar, makes it accessible via reflection, and sets it to zero when any of its own client-sided item groups are deleted -- which means it isn't really possible for us to do this.

If anyone looking at this wants to PR/implement a fix in CC, it's a matter of checking whether quilt$currentPage is there instead of fabric_currentPage.