I have a HP mediasmart server that attempts to automatically configure port forwarding to enable my home website and remote access. This all worked well in 1.21 and 1.22b, I seem to be having issues with it in 1.31.
Like the OP, I am experiencing the same problem with the DIR-655 and FW 1.31 and Windows Home Server that I did not experience under 1.21.
The Console will complain of port forwarding failures often. Opening the Home Server Console, going to "Settings", then "Remote Access" and selecting "Repair" will often restore proper function, but it will shortly complain some minutes later that port forwarding has failed once again (persumably during some sort of periodic renegotiation?).
Problem persists after a 30-30-30 reset, and entering the router configuration again by hand from scratch.
Since the only change was upgrading the router firmware to 1.31, I can only conclude the fault lies there. For that reason alone (compounded by the inability to downgrade to what was a working version), I'm very unhappy with this firmware release. This feature worked properly in earlier firmware releases.