No, not had this on mine. My understanding is that the interior sensor is volumetric so it would have to take a change in volume to set if off? :? Are you getting lots of water in at the a-pillar? :?
Mine seems to be quite sensitive about the bonnet being closed properly - sometimes complains after I've had it open to top up windscreen washer fluid. I usually need to make sure its firmly closed or else it warns me. Could it be something like that maybe triggering the alarm?