R* also told me to turn UnUp off, for me that elevates my Nat from 2 to 3, which causes me to always join empty servers
If you haven't rebooted yet, I would try shutting down your PS3 and booting back up.
I know when the update was released a couple weeks back it did not work at all once the update installed. After some frustration I found that a reboot was all that was needed (was the same for many others).
At this point I'm guessing you've tried it, but that's all I got (Other than the UPnP setting discussed in the other thread).
I did as someone said. Turn off your upnp in network settings and it seemed to have done the job. Horse comes to me when called, No glitches (at least as I can see) and best of all, now lag free. I would suggest doing that as well