It will also occur at the following URL
https://toku-p.earth-car.com/login

Is this only happening on iOS?
Did you check on other platforms (with Chrome)?

Yes. Only Chrome of iOS (iPad) came out.
It has not happened in browser chrome or other browser on iPad/PC.
 

This is likely to be web site dependent. Since Chrome fills forms using JavaScript and depending on the web site's JS, they may incorrectly think that user hasn't entered anything into the username / password field(s).

This happens on some other web sites too.

(Use google translate to change summary to English to help with future triage.)

So it is passwords and not autofill

It's likely affecting both. I consider JavaScript filled forms are not also recognized by web site's (JS-based) validation checks as "filled by human".

I think this is because we trigger a "change" event and not an "input" event.

This is one other case I've "fixed". Can you think of a different/better fix?
https://chromium-review.googlesource.com/c/chromium/src/+/615363

You can also send an 'input' event
like the answer here:
https://stackoverflow.com/questions/42795059/programatically-fill-reactjs-form

This works for filling fields on React powered pages, and maybe with other frameworks.

We can do the same way as Password Manager & Autofill is doing on other platforms, namely to send all possible input related events: focus, input, change, blur events

Blink code that doing this is here https://cs.chromium.org/chromium/src/third_party/WebKit/Source/core/exported/WebFormControlElement.cpp?sq=package:chromium&dr&l=95

OK. Thank you for your kind response. I would like to check this javascript a bit more.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/55518e17850cac0bdc6fca7b24092bea479e34db

commit 55518e17850cac0bdc6fca7b24092bea479e34db
Author: Olivier Robin <olivierrobin@chromium.org>
Date: Fri Dec 01 15:32:35 2017

Send input event on element change.

Some javascript frameworks (e.g. React) or pages have a cache version of input fields in
pages.
This cache will override the autofill value of the fields.
When value is changed, events must be sent to update these cache.
When a user type in a field, the following events are usually sent:
- keydown
- input
- change
- keyup
By testing, most framework use use one of these events, and some framework use
the data field of the event as new value.

Send these events when updating fields.

Bug: 783025, 728631, 732360
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I147a4471ecd2e389cfca57d2aa9d78f61360aa61
Reviewed-on: https://chromium-review.googlesource.com/771674
Commit-Queue: Olivier Robin <olivierrobin@chromium.org>
Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Reviewed-by: Peter Lee <pkl@chromium.org>
Cr-Commit-Position: refs/heads/master@{#520946}
[modify] https://crrev.com/55518e17850cac0bdc6fca7b24092bea479e34db/components/autofill/ios/browser/resources/autofill_controller.js
[modify] https://crrev.com/55518e17850cac0bdc6fca7b24092bea479e34db/ios/web/web_state/js/resources/common.js

Thank you very much. Here I will respond to you tomorrow so we will respond.

I confirmed it at the latest version of 63.0.3239.73, but it seems I have not fixed it. .
We are planning to deal with it separately by javascript on this side.
Thank you very much.

The solution from comment 14 is implemented only for non-password autofill, so it wouldn't change anything password autofill.

I've tried the same solution for Password Autofill. While I'm not sure whether it would fix for the site from this bug, it breaks filling on reddit.com (only username is autofilled on reddit with the fix). So I'm not sure whether it's worth to implement emulating user autofill by sending change events. On other platforms we had some bugs related to this.

I leave this bug open, if somebody would like to investigate what would be consequences in making this fix and whether it's worth to do.