There are problems in the rt2800usb driver on Linux and according to this post I have to set nohwcrypt=1 for the rt2800usb kernel module.
sudo ifconfig wlan0 down sudo rmmod -f rt2800usb sudo modprobe rt2800usb nohwcrypt=1 sudo ifconfig wlan0 up
To make it permenant I have to put the following in /etc/modprobe.d/rt2800usb.conf
options rt2800usb nohwcrypt=1
Damn it… I really should have found this earlier…