This bug is fixed. But is a part of the upcoming PR1.2 update. NO dates have been announced. But its expected soon considering its in testing internally by Nokia before its released to the public.

https://bugs.maemo.org/show_bug.cgi?id=9084
and related to
https://bugs.maemo.org/show_bug.cgi?id=6823

Looks like its caused by playing certain types of videos. I know its no solution, but you could avoid any new videos you've added for the time being or simply restart the phone when you notice high CPU usage.