versions move backwards with freebsd-update(8)

[John]

Hello freebsd-questions,

I have a netbook running as a small server, running freebsd 10.0-RELEASE-p5.
I've not used frebsd-update before, but thought I would try as it's running 
RELEASE, and it would otherwise take ages to upgrade as it's only an atom n450
with 4GB ram. It runs i386 rather than amd64.

I do this:

root at samsung:/usr/ports # date
Wed Jun 25 02:55:23 BST 2014
root at samsung:/usr/ports # uname -a
FreeBSD samsung 10.0-RELEASE-p5 FreeBSD 10.0-RELEASE-p5 #0 r267600: Wed Jun 18 21:16:17 BST 2014     root at samsung:/usr/obj/usr/src/sys/GENERIC  i386
root at samsung:/usr/ports # cd
root at samsung:~ # freebsd-update fetch
Looking up update.FreeBSD.org mirrors... 5 mirrors found.
Fetching public key from update2.freebsd.org... done.
Fetching metadata signature for 10.0-RELEASE from update2.freebsd.org... done.
Fetching metadata index... done.
Fetching 2 metadata files... done.
Inspecting system... done.
Preparing to download files... done.
Fetching 5 patches... done.
Applying patches... done.
Fetching 37 files... done.

The following files are affected by updates, but no changes have
been downloaded because the files have been modified locally:
/etc/defaults/rc.conf
/var/db/mergemaster.mtree

The following files will be updated as part of updating to 10.0-RELEASE-p6:
/bin/freebsd-version
/boot/kernel/kernel

[loads of other files]

root at samsung:~ # freebsd-update install
Installing updates... done.
root at samsung:~ # uname -a
FreeBSD samsung 10.0-RELEASE-p5 FreeBSD 10.0-RELEASE-p5 #0 r267600: Wed Jun 18 21:16:17 BST 2014     root at samsung:/usr/obj/usr/src/sys/GENERIC  i386
root at samsung:~ # shutdown -r now
Shutdown NOW!
shutdown: [pid 2920]

[...]

Last login: Wed Jun 25 03:00:59 2014 from 192.168.1.210
FreeBSD 10.0-RELEASE-p4 (GENERIC) #0: Tue Jun  3 12:52:18 UTC 2014

?!!

$ uname -a
FreeBSD samsung 10.0-RELEASE-p4 FreeBSD 10.0-RELEASE-p4 #0: Tue Jun  3 12:52:18 UTC 2014     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC  i386

I'm expecting p6 and instead got p4. What gives?
-- 
John