Karl--
I've noticed occasionally my QMX yields clicks instead of sidetone. My guess is at those times my transmitter has shut down. Maybe it detected a bit more SWR than it wanted or some other thing. Cycling the power (and also possibly fixing the antenna/tuner issue) usually seems to resolve the problem.
That fact that you got a sidetone today suggests to me that ambient conditions were different today and your QMX decided it was safe to come out to play!
73 es GL de Todd W2TEF
Todd W2TEF