genkernel can't determine kernel version properly if kernel was built with --kernel-outputdir option. Reproducible: Always
Created attachment 392652 [details, diff] Fix get_KV for kernel built out-of-tree
This should have been fixed via https://github.com/gentoo/genkernel/commit/58a57b303efb9fb5ce60c0dc40c806e7d7b46db0. Please file a new issue if you still have that problem.