Car headlights shining through a window onto detector ?

Hi sorry to re post but I tested again tonight and got a false alarm, twice

As I previously said, the alarm was being triggered between 8:15 and 8:45 when it was fully set.

On Thursday past the alarm was triggered at 8:35 on zone 4 landing...sharp beeps, I reset it and it triggered again at 8:45. I could see nothing odd but my view point was partial view out front.

Tonight, on full set at 8:35 the alarm was triggered panel said zone 4... Sharp beeps. I rushed to a front bedroom window, nothing unsusal.

Rushed back to the panel and put it on full set ( to see if it would trigger again)

When I got back to front window I could see the elderly neighbour coming out of their front door, with garage door already open, she got into her car and drove it into the garage, walked out and closed the main garage door ( could not see if this was manual or electronic), she walked back into her house and 2-3 mins later at 8:45, my alarm triggered a false alarm on zone4, landing.

The elderly neighbours do not always have their car sitting in the driveway, they only take it out if they are using it that day!

They also have an alarm system, I do not know the details.

What are your expert thoughts on this? Either my theory is daft and pure and simple I have a faulty landing sensor that triggers at 8:35 and 8:45 when alarm is fully set.

Also to note, it does happen quickly but I don't see sensor 4 flashing and it only indicates it's zone 4 after I have silenced the alarm.