"We find evidence that 38.52% websites installed third-party event listeners to intercept keystrokes, and that at least 3.18% websites transmitted intercepted information to a third-party server, which aligns with the criteria for wiretapping."

They say they autopopulate fields based on field type, but address fields are common to have an autocomplete feature enabled. That would require transmitting data before submitting the form. I didn't see anything about rating probabilities of the transmitted data being benign and useful or nefarious and malicious.

The article is talking primarily about third-party tracking scripts. These would not be providing autocomplete to first-party forms.

The article does talk about one example which is not considered wiretapping: a Google search field with autocomplete that's intentionally embedded in the web page.