A kernel was released that changed how the hash value got computed for casefolded filenames. (used for better windows compatibility) That kernel then went into production. This unfortunately split some file-systems that supported this into two incompatible versions, breaking the kernel rule 1.
There might now exist file-systems were created/modified with this bug present that the old/fixed kernels can’t understand.
$ gdb -ex 'file /bin/gdb' run corrupted double-linked list Thread 1 "gdb" received signal SIGABRT, Aborted.
Yeah, try debug that.