Wireshark: Alfa AWUS036H not capturing TCP

Hi everybody

I am using Alfa AWUS036H usb Wifi device with Arch Linux (kernel 4.3.3) to capture wifi traffic. I have setup an open access point which should be easy to sniff. I tried for many days but couldn't catch any tcp data. There were numerous protocols like 802.11 broadcasts, NBNS, UDP, ICMPv6, ARP, SSDP, LLMNR etc but no tcp. Then I booted a live kali cd and repeated the same procedure exactly. This time everything worked fine and there was plentiful tcp traffic from multiple APs nearby.

My procedure: I put the device in monitor mode using 'airmon-ng start wlan0'. Then start capturing data using 'airodump-ng wlan0mon' so I start seeing info about nearby access points. At this stage I start data capture on Wireshark. Here onwards, Kali gives loads of tcp data but Arch doesn't capture a single tcp packet.

My question is: While both Arch and Kali systems are using the same driver (rt2800usb version 2.3.0), why can't I capture tcp on Arch?

Regards