Linear Z-Wave Alarm/Strobe (WA105DBZ) Went off by Itself - How do I investigate?

I’ve had the Linear Z-wave Alarm/Siren/Strobe for about two years. To the best of my knowledge, it has never gone off before. In fact, I am pretty sure I don’t even have it pointed to within any automation. Yesterday evening it went off. After turning it off, I went into the IDE to review what may have caused it to trigger. I can see where it was polled historically, and then I can see it received a signal to turn on from source “DEVICE digital.” When I turned off the siren, the source is “DEVICE.” Any idea how I could determine what “DEVICE digital” may be?

Thanks in advance.