The problem was that for a bit both the old and the new server were running, and the update to the DNS records takes time to propagate throughout the DNS servers across the world.
So, some posts have ended back to the old server.Since it's too much hassle to merge them with the new ones (duplication of post IDs and such things), I think we'll just consider them 'lost'.

Shouldn't be a problem anymore as the old server is beered again (well it's been for few hours now).