iMac restarted after power failure

[Crash Davis]

I have a 2011 iMac. The Energy Saver setting to restart after power failure is NOT checked, but today the power went out, drained my UPS, and then shut down and restarted. After it was back up for a few minutes, the UPS was probably under the shutdown threshold I've set, so it shutdown again. This time it stayed shutdown.

So, kind of strange. Anybody have a similar experience?

 

[Detrius]

There's some important information missing from this chain of events... when did the power go out, when did the battery die, when did the power come back on, and when did the machine turn on?

The way it's written, it sounds like the machine turned on when there was no power.