I'm seeing what I think is the same problem. I've been having issues printing with AirPrint for months. I thought it was the printer so replaced it with another from a different manufacturer, but it has exactly the same issue. I pinned to the problem down to Link-local IPv6 communication. Today, I tried to enable IPv6 on the router and added IPv6 to my subnets. The wired connections are all still working perfectly. But the Wireless EAP325-Wall connections are unusably slow, seem to block communication. Reverting these to firmware 3.1.1 (which does not claim to support IPv6) seems to solve it. This removes the ability for the EAP to be assigned an IPv6 address itself, but the clients still get an IPv6 address, and seem to work ok.