Well maybe....
this is just a suggestion..
my alarm kept going off all the time, 5-6 times a night wasn't uncommon. Anyway i took it back and it is apparently a common fault, something to do with the gps antenna for the tracker interfering with the alarm. Anyway i had a nosy after the fault was rectified and the antenna is a biggish black disc about the same diameter as a tennis ball and about 10-15mm thick. The point being it doesn't actually appear to be fixed down. Now as it is above and left of the stereo it maybe rattling and the sound travelling. As pulling out the stereo is a 10 minute job it might be worth a look.