If you have an aftermarket alarm, can you tell me if you have problems with the alarm thinking a door is "open" when the alarm is armed?

I bought an Autopage two-way alarm and I had it installed at a very reputable dealer. The installer says the alarm turns on before the 'door system' signals that all doors are closed, and there is no way around the false door open condition.

Is this bull or does this happen to anyone else?