Are these outages caused by introduced bugs, though, or by load issues?

As someone who has spent many years working in high load environments, this is not an uncommon pattern.

You design a system and it works great. It can handle failures, load spikes, it is horizontally scalable, things are great. You think you figured it out.

And then load keeps increasing and you suddenly hit a tipping point where everything keeps failing, and you cant keep up. The things that you thought were perfectly horizontally scalable turn out to have a bottleneck you didn’t even think about until you got to a truly massive scale. Your systems suddenly don’t have the excess capacity to handle load spikes or catchup work, so suddenly any failure cascades and recovery is more and more difficult. You can’t solve the problem with additional hardware, and your perfect scalable design actually can’t scale any more.

This doesn’t have to be about GitHub using LLMs in their code to still be related to LLMs. GitHub gets a lot more commits now because of LLMs and probably get a lot more reads because of LLMs as well.

It could be that the extra usage just pushed them past one of those capacity thresholds.