Yes, my aftermarket alarm would invariably exhibit the same behaviour - one of the regular spots was a car park where with a nearby building with mobile phone masts in the roof. Luckily, knowing where the control unit was, opening the door manually (and triggering the alarm), and pressing the keyfob disarm button in the vicinity of the control unit usually did the trick.
Once I got a call from a friend who mentioned that other people in the car park appeared to be having problems with their car alarms as well - I asked where she was at the time - she was not far from a certain establishment in the south coast with naval radars and communications masts - I said to get inside the car and try to disarm - it worked.
Biting the hand that feeds IT
