E.g. say you chose Sol as your default in Cursor, but Opus is your 2nd choice, it's going to give up on Sol after a few tries and switch to Opus
Or you have copilot code reviews set up, and it falls back
Etc
With AI it's even easier to trigger problems like you say. Capacity is so constrained by compute that outages are common. Because outages are common people/AI develop failover systems in their harness. When a big system has issues, suddenly everyone has issues.
It's almost an expected emergent behavior.