Phantom Alarm with No Visual or Known Issue

New '24 WildTrak, Sas, Lux, 4 door owner here. I had a strange, steady whistle alarm sound at startup without any visual warnings or obvious indicators. After checking all the doors and seat belts, I decided to make the 3 minute trip home to figure it out. It was a steady beep, not to loud, but enough to be annoying. When I arrived home, I used my automatic garage/gate opener to close my gate, and the sound just stopped suddenly. The alarm started over 2 miles from home, so I'm reasonably sure the gate is not involved. I have absolutely no clue what occurred or why, maybe there is an issue with my visor switches that house the garage/gate opener. The owner's manual, worthless. Anyway, are there any similar experiences or insights? Thanks for any light you may shed on this issue.
/Steve