I think down detector doesn't actually have any probes or actual insight into status etc. I think it uses search volume on its own service as a proxy for an outage - so if e.g. lots of people rush to down detector to query to see if SERVICE_FOO is down, it will register as an outage on down detector because loads of people are trying to see if there is an outage even if SERVICE_FOO is actually totally fine.
My hunch is everyone saw that openai and Claude were down and checked for Gemini too. I was using Gemini the whole time this happened without a blip so it certainly wasn't down in my region at least. 3.8 flash is pretty good and didn't miss a beat.