Accuracy on Real Time Clock

Has anyone else noticed a very large clock drift on their revision B4
or possibly even B5 boards? (I haven't taken my B4 offline long
enough to remove C70 or even RMA it due to serial issue #8, it's auto
building kernel deb's with lenny/sid/mojo chroot's)

I'm running Koen's Kernel build on debian lenny, patch level R12:
Linux debian-armel 2.6.27-rc7-lenny-oer12 #2 Tue Oct 7 23:27:25 CDT
2008 armv7l GNU/Linux

and i have ntpdate run as a cron job every hour..

Normally ntpdate has a reasonable amount of drift, but on a regular
basis the time is way off: here's a log extracted from the internal
cron mails's:

9 Oct 03:45:07 ntpdate[3858]: adjust time server 192.168.1.85 offset
-0.282079 sec
9 Oct 04:45:01 ntpdate[27405]: adjust time server 192.168.1.85 offset
-0.200077 sec
9 Oct 05:45:01 ntpdate[27425]: adjust time server 192.168.1.85 offset
-0.223486 sec
9 Oct 06:21:35 ntpdate[27486]: step time server 192.168.1.85 offset
-131005.592022 sec
9 Oct 06:45:01 ntpdate[27646]: adjust time server 192.168.1.85 offset
-0.109322 sec

Strange