Hmm. Not that it helps much, but I haven't yet seen this issue on my N900s. One point of interest, though -- browsing through the threads, it looks like everyone thinks widgets are the cause (although nobody seems to have pinned down a particular offending widget). I actually don't run any widgets, which may be why I haven't hit the problem yet.

Is there a difference in the widgets running on your test machine and your stable machine?