The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9f7279479f4be59322d1e6146afe9200282887c5

commit 9f7279479f4be59322d1e6146afe9200282887c5
Author: sebsg <sebsg@chromium.org>
Date: Thu Apr 19 21:04:11 2018

[AF] Update dynamic form with cached form data if it exists.

Bug:  834921 
Change-Id: I35b6f7f72fa1253adf41092eed47761bad31725a
Reviewed-on: https://chromium-review.googlesource.com/1020075
Reviewed-by: Roger McFarlane <rogerm@chromium.org>
Commit-Queue: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552153}
[modify] https://crrev.com/9f7279479f4be59322d1e6146afe9200282887c5/components/autofill/core/browser/autofill_manager.cc

sebsg@,
Could you please provide us the exact steps to verify the issue from TE end.

Thanks..!

It might be a bit hard to test, but there is a good example of a site that is fixed by this CL: https://shop.lululemon.com

Make sure you go to the US version of the site.

Make sure you have a valid Autofill address with a valid state and the country set as US

Add something to the cart and go to guest checkout.
Change the country to anything except the US
Trigger Autofill on the First name field for example.
When the country changes, you should see the state get filled automatically right after