Could be the IO? I remember colleagues working on getting stuff running on azure and they experienced horrible IO latency, as well as very low throughput for lots of small IO (aka unix-style software).

Was a few years back so it might have improved since, but if those things are still non-optimal and github is built with a unix-style vision of tons of small IO access…

This specific outage taught me that github apparently stores git repos on-disk which I was not expecting though (because the API access complained it could not delete repos until they'd fully backed to disk or something).