Backend Authentication SM problem?

[Teresa]

Dear all,

According to the Backend Authentication state machine,
An "Access-Reject" packet received from Authentication server,
so the state machine should jump to "FAIL" status....
Here is a problem.....once I input the wrong identity (wrong user name or
password),
the state machine jump to "TIMEOUT" instead of "FAIL"...which is odd.
AP did receive reject packet from RADIUS, how come enter into TIMEOUT
stage????

Here is the debug message:
Incoming RADIUS packet did not have correct Message-Authenticator - dropped