I think it probable that it is a memory leak issue, but it does occur with well established programs - I have it regularly running drPodder, email and browser - nothing else.
However I don't see it running drPodder and other applications, so it seems to me it may be the email or browser application and NOT drPodder.
The other issue I have is the Camera refusing to save photos, again solved by a reboot. Is this a similar memory leak issue.
In other words, it seems to me the stock programs are part of the problem.