Could “possibly” be the notorious tailgate wiring issue. The harness tends to break down/short out where it passes through the LH tailgate hinge. That was the problem with my tailgate unlatched warning (along with a few other electrical issues like blown fuse for the fuel door, etc). It might also be causing your alarm to think someone is breaking into you rear windscreen. Maybe try pulling the fuse(s) that feed some those things that are tailgate-related or exercise the tailgate open and closed and see if that stops, or reduces, the alarm from going off.