The bug appears to have been introduced in some FreeBSD 13 version.

I run FreeBSD servers that do not have this bug. In my "kern_exec.c" there is no "consume" anywhere. There is also no "memmove" at all.

That file was last patched in 2024, but whatever changes had introduced that bug, they were not back-ported to older FreeBSD versions, so those are not affected.