Did you get vaccinated? If so, did you supply your email address related to your Google account on the form or enough other information to link the two? Did you read all of the related documentation? I wouldn't be surprised if they slipped somewhere on the form that you were agreeing to it.
I did supply my email but it's not a Gmail or Google for Work email address nor a domain tied to those. Exposure notification is clearly off. Still got the app.
