I love that you Support guys are trying to help us but could you please send this to the higher ups? This only started happening with the new Dash release, so for about a month or two. I've tried everything, I've called, tweeted and no help on this subject. Like I said before, these topics have been popping up ALL over this forum.
Me and my friend have:
Rebooted routers, modems, xbox's a ton.
Reset router and modems to factory settings several times.
Reset all Xbox network settings several times.
DMZ's, Port Forwarded, SAME settings as before.
We both have same ISP, not the problem since same local friends all have same ISP.
NAT's are always OPEN.
Its a problem with Xbox Live and its ruining my experience. I've had XBL for 8 years and can say this honestly is the only time I've been annoyed by something. Would love to see this fixed soon.