DST atomic clock

I have one of those atomic clocks, that are supposed to update automatically. For the several years now that I've had it, it never caught the Daylight Saving Time time change. I let it go once, and it corrected itself Monday night.

I did some research, and learned that it checks itself at midnight. Which, of course, misses the DST change, because that happens at 2am.

Then, yesterday, I got up and it had reset itself properly.

WTF? Did they somehow distribute an update through the time signal? (Seems impossible.) Was my research that said it updated at midnight wrong? (Seems much more likely.) But if so, why didn't it ever update automatically for the 5+ years I've had it?!

I thought technology was supposed to make our lives easier, not more puzzling.