If you ballpark it as a single 3 hour downtime window per week and iid Poisson, then overlapping downtime probability of 2 providers is approximately the expected occurrence rate per 3 hours, 1/56. Not particularly surprising at all.

If it's a "thundering herd" problem where everyone's harness falls back to less popular providers that don't normally see that much demand, I'd say the probability is pretty good.

Classic cascading failure is consistent with providers failing 80 minutes apart instead of simultaneously.

"precisely the same time" meaning 80 minutes apart?

Yesterday it was 100%

"All of these" is two. OpenAI had a router issue. Anthropic had a separate issue. Anthropic uses a lot of SpaceX compute, so an Anthropic issue and a SpaceX issue can be one in the same, as was likely the case this time.

And they weren't down at precisely the same time. Anthropic's issue started ~1 hour before OpenAI's.

Pretty high?