It still does it on a clean install. When the problem started I had upgraded it, but in the meantime needed to do a reflash. Another weird behavior that it's done before that I forgot about untill this morning, is it was fully chrged and still on the charger, I killed hildon desktop to update the icon cache after updating a program, and when the device came back on , it showed the battery as very low then a few seconds later showed the fully charged battery icon.