uname -a and freebsd-version show different output on my system

[Dino Vliet]

Dear peeps,I'm running freebsd11 in a virtualbox production machine and something really bothers me a few months already. I have the idea that freebsd-update is not installing the new kernel as uname-a shows:
11.0-RELEASE-p2 FreeBSD 11.0-RELEASE-p2 #0: Mon Oct 24 06:55:27 UTC 2016     root at amd64-builder.daemonology.net:/usr/obj/usr/src/sys/
However freebsd-version shows:11.0-RELEASE-p6
I have done various freebsd-update fetch  followed by freebsd-update install but after rebooting, the uname -a shows no different output.I must be doing something wrong but don't know what.
My /etc/rc.conf is:clear_tmp_enable="YES"
syslogd_flags="-ss"
sendmail_enable="NONE"
hostname="webprod.imiana.com"
ifconfig_em0="DHCP"
local_unbound_enable="YES"
sshd_enable="YES"
ntpd_enable="YES"
pf_enable="YES"
pf_rules="/etc/pf.conf"
pflog_enable="YES"
pflog_logfile="/var/log/pflog"
# Set dumpdev to "AUTO" to enable crash dumps, "NO" to disable
apache24_enable="YES"
postgresql_enable="YES"
dumpdev="AUTO"
kern_securelevel_enable="YES"
kern_securelevel="3"
When I update with freebsd-update I first start out the kern_securelevels, then reboot and then use freebsd-update followed by freebsd-install. If everything finishes correctly, I enable kern_securelevel again.
How can I fix this?