There has been a lot of fear, uncertainty and doubt and confusion around this topic.
At last I have this fixed per:
https://github.com/discourse/discourse/commit/918a0ea3a428e0e3ea4bcfb887df711bc895c0d8
I had a double repro on local (both in canary and latest chrome). I confirmed autocomplete="random-non-off" string fixes it.
This was an intentional break by Google, cause they know better ™
https://bugs.chromium.org/p/chromium/issues/detail?id=468153#c164
The tricky part here is that somewhere along the journey of the web autocomplete=off become a default for many form fields, without any real thought being given as to whether or not that was good for users. This doesn’t mean there aren’t very valid cases where you don’t want the browser autofilling data (e.g. on CRM systems), but by and large, we see those as the minority cases. And as a result, we started ignoring autocomplete=off for Chrome Autofill data
So now, when we do not want autocomplete we simple set autocomplete="discourse"
I am not sure if we will backport this to stable or not, you will need to be on latest.