ExpressCard adapter deauthenticates from a WPA network
A user fitted an external ExpressCard 802.11n adapter that is listed as supported, but could not stay connected to a WPA network. The log showed the client deauthenticating by local choice (reason 3) about every two seconds, and the supplicant connecting and dropping in a loop.
They shared debug output elsewhere and asked the community for pointers.
Takeaway. The cause was not settled in the report. A connect-and-drop loop every few seconds is worth testing with a minimal configuration, a newer kernel and a different regulatory domain, as possibilities to rule out.