@stefano I bet the LMM agent upgraded and rebooted FreeBSD without updating the boot code, something which is documented in both the FreeBSD upgrading instructions and in the FreeBSD handbook.

@slothrop @stefano With the old freebsd-update method, it's:
freebsd-update fetch && freebsd-update install

With the new pkgbase method (FreeBSD 16 will remove freebsd-update), it is:
pkg update && pkg upgrade