It might be related to the other post here about RC2 dislplay age limited, not sure.
I have RC2 downloaded but never tried it (yet?), moved from RC1 to RC3 directly.
With RC3, in a group posts view or whatever it is called, first I noticed that search results are wrongly empty, while with RC1 everything was ok.
Then I downloaded all headers for some groups - and "Show all posts" shows an empty window too with 0 results.
So I returned back to RC1 and everything is back to normal, the posts now are shown as they should be.
Never tried RC2, though. So not sure when the problems started, in RC2 or in RC3.
Anyway, I think I will wait for RC4