[Xbox One] Asus RT-N66U issue on Xbox One

Hello,

Recently I bought an N66U router and have been having issues in BF4. Either the game is laggy or I lose connection entirely. My internet is the same as before and stable, and my router shows port 3074 being forwarded via UPNP to the right IP. Is there something I'm missing? I used UPnP on my last router and it worked fine.

Edit: Solved the issue. For reference, I flashed Merlin's firmware and it fixed it right away. The latest Asus one must have some bug in it.