Fire alarm goes off! (System Sensor L-Series horn/strobes)

I caught a fire alarm going off "in the wild" on my way to do some grocery shopping today. I initially suspected it to be a test, but I felt it would be better to call since nobody seemed to be there. There was fortunately no fire, but the alarm was still sounding after I finished shopping.
Also note how much more crisp these L-Series signals sound compared to their predecessor, the SpectrAlert Advance, in this video:
• Fire Alarm Activation ...

[@adamk9652]

Yeah today at my work the fire alarm also went off (3rd time this week too! ) Dust in the duct detector paired with the AC caused it to go off AGAIN. This module has been in trouble for the past 3 months. Yeah Spectralert Advances are pretty loud,😑. Thankfully a service call was placed so hopefully they can fix it.

[@FESPerson2974]

I got to say it’s Rarely to hear a fire alarm go off

[@abandonedmass2333]

At first I thought they were testing them because the building looks new but then you said it was a false alarm

[@josephfrye7342]

these system sensor are excellent too but they can be speaker stroke or also horn strobe

[@boydalexander4652]

The monotonous alarm sound

[@GaryBeltz]

Did you ever find out what set it off?

[@Fahrenheit4051]

Loneliness.
(JK - I have no idea)