Good to know. Last night my BB crashed with one of the famous 'error 523 reset' death spirals that might or might not have had something to do with the sync problem, so I ended up having to rebuild the whole thing from scratch. So far I haven't reinstalled any 3rd party apps and the thing has been working fine and cooperating with DM. I'm planning to proceed deliberately from this point forward.
Were you able to determine anything about the content on the four problematic cache entries?