Chrome Version       : 62.0.3202.94
OS Version: 
URLs (if applicable) : www.labanquepostale.fr
Other browsers tested:
    Firefox: OK

What steps will reproduce the problem?
1. Navigate to: www.labanquepostale.fr
2. Tap the "Acces Comptes Particuliers" button.
3. Scroll down

What is the expected result?
The page adds the .modal_open class on the document body which has overflow: hidden. This means there should be no scrolling possible and the URL bar should not be movable.

What happens instead of that?
The URL bar can be hidden. This causes a resize on the page which then causes (for some reason) removal of the modal class and the overflow: hidden style.

This makes the page usable on Chrome but not on Firefox since it correctly doesn't allow the URL bar to hide so it's a bit of an interop issue. (Though a resize via rotation still makes it functional).