Thats why nstreme rules , almost I never use nv2 on p2p linksI had the same problem.
When nv2 is used i cant't send more then 10Mbit/s i TCP. First bandwitdh test after wlan reconnect is correct 50 Mbit/s in 10MHz channel width but second bandwidth test show max only 10Mbit/s.
I have used ROS 6.20 and wireless-fp. Test is do between 2x sxt.
Interface queue is set to hw-queue-only for eth1 and wlan1, connection tacking is off.
But when I change to nstreme i have 45Mbit/s in TCP test with 1 connection
IMO in nv2 protocol something is wrong in TCP connection