A bit behind the times?
"There's an effort underway to support “'N+1 redundancy at the facility level'"
1) If you're not running N+1, then you've not learned the first lesson of SRE.
2) For the repos (not all the cruft GitHub has added to them), unless you have a hash collision, resolving "some writes here, some writes there" is trivial by the design of git.
3) For the local cruft, adding shadow git repos to handle their changes should be at worst simple. Again trivial to recover from split brain.
4) For the non-local cruft (ie: webhooks), yes, there would be work to be done to deal with the fact that apparently there are people allowed near keyboards that think that IP is a reliable system for data transport.
What am I missing here?