Intermittent electrical problems are tricky. Have you had a windscreen change done at some stage recently. Has it been raining, have you washed your truck or under the bonnet recently. A bad connection on a connector or ground is a probable cause, or a shorted connection in a connector to the next pin by some water is also a probable cause. Pure water is an insulator, but water that leaks in from your windscreen and runs down your wiring harness is not pure, and will have soap and dirt in it etc, and this is enough to allow electrical current to flow and upset things. Lots of other possibilities but this is a common cause of probs. Water could also be in your door lock mechanism and cause a problem. Because each door switch and bonnet switch is tied to the alarm circuit I would investigate those as well. If you are in the car and it happens, keep an eye on your dash lights and see if a door open indicator light flashes on at the same time. The actuation of the rear door or either front may have a bearing on it. Check there is no play and the door latches are set correctly..............Good Luck