World upgrade is blocked due to genkernel (PYTHON_SINGLE_TARGET update)

# emerge -a -uUDN --with-bdeps=y --keep-going world
<...>
Local copy of remote index is up-to-date and will be used.

These are the packages that would be merged, in order:

Calculating dependencies |

!!! Problem resolving dependencies for sys-kernel/genkernel from @selected
... done!
Dependency resolution took 10.90 s (backtrack: 0/20).


!!! The ebuild selected to satisfy "sys-kernel/genkernel" has unmet requirements.
- sys-kernel/genkernel-9999::linux-be USE="firmware zfs (-ibm)" ABI_X86="(64)" PYTHON_SINGLE_TARGET="-python3_10 -python3_11"

  The following REQUIRED_USE flag constraints are unsatisfied:
    exactly-one-of ( python_single_target_python3_10 python_single_target_python3_11 )

(dependency required by "@selected" [set])
(dependency required by "@world" [argument])