Comment by phil21

Could also just be a bunch of IoT devices running on synchronized time source that have what amounts to a defrost cronjob. And a latent bug that due to everything being synced and on the same schedule failed in the same manner (eg crashed the controller immediately after turning the heating element on and either didn’t boot back up or booted and some shitty programming forgot to check the heating element status). Saving state across boots or having a race condition of some sort like this gets my vote - since it’s a pretty common failure mode junior programmers are susceptible to.

I’ve seen similar too many times in my career - synchronized clocks are great until someone deploys a cronjob that fires at exactly the same time across the fleet and it breaks a certain OS or firmware revision. Which then exposes another bug that exists globally.

I definitely still subscribe to don’t attribute to malice what you can attribute to incompetence mindset.

Certainly all speculation though, real root cause will be interesting if it ever becomes public.