Hi, I too have T3 timeouts in my log, I've done the port forwarding, only way I could get open NAT using the Ubiquiti router unfortunately.
It is very random and no pattern except maybe when I'm on a great kill streak lol (which is rare)
I had the same setup on Sky except the Ubiquiti and it never happened, I have already moved my TV back to Sky and looks like I will have to do the same with my BB, I have my BB primarily for gaming and its not really suiting my needs. I'm even thinking of getting a cheap BTO service just solely for my Xbox until my VM contract is up
I bought the new Ubiquiti router as I thought it was my Asus router maybe starting to fail but I still have the same issue with the new router.
I don't bother calling them anymore, due to my profession involving a lot of network troubleshooting they frustrate me asking me too reboot my router, put it in router mode, change the wifi channel, script rubbish. Things like insisting changing the WiFi channel on my Hub3 in modem mode will help my WIRED Xbox drives me mad lol