The valid autocomplete values are listed in the spec here: https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#set-of-space-separated-tokens
It seems that this Google Form only has one input field that has a valid autocomplete value, which is the email. For that particular field, I’m not sure why this doesn’t trigger a selection and I would need to dive deeper into it (currently don’t have time for that though). The same doesn’t work in Chrome either.
The other fields definitely don’t have the correct autocomplete value, so those not being filled out makes sense.
Hope this helps 