Looks like they only disabled it in Brazil [1].

1. https://www.theverge.com/news/613572/google-earthquake-detec...

Did they ever follow up on the outcome of that investigation and report on what caused the false detection?

The page is still up: https://crisisresponse.google/android-alerts/

And according to some Googling, they had only disabled it in Brazil while investigating why the false alarm happened.

Is that even slightly proportional? One wrong warning- vs 1 right..