It was 2018. As someone who worked at GitHub during the Microsoft era, I think Microsoft was a pretty reasonable steward of GitHub right up until Copilot started getting popular. After that, leadership stopped investing in the core product and infrastructure and either incentivized people moving into the Copilot org or just fully reorged teams into it regardless.

The load increase from AI is definitely significant, but I think with proper investment they would not be having this many issues.