Your first answer confuses me.
Usually, my smoke alarms activate in the repeating fire tone pattern when the batteries are low. Only when we disconnect the smoke alarms from the system do they chirp, and by chirp i mean just one little chirp. We’ve had this happen twice within a year, October 2020 and this February. Usually before my room’s smoke alarm goes off, I hear another alarm outside of my room.
I do have a theory though… maybe it’s the smoke alarm in the basement. Where we live, we bought the house WITHOUT a finished basement, which dust might be floating around and triggering the alarm. Unfortunately, and most dangerously, we’ve never tested our smoke alarms. Not even a push of the test button. I could ask my parents, they’d probably deny it.