iOS overlay cursor position issue

Intro: I work as a product owner in a cloud based contact center solution provider company, and for our web chat feature, our customer's customers using iOS devices are having problems filling in their contact details in the chat's input fields. The chat is contained in an overlay/modal on our customer's main site. On mobile devices this modal is more or less filling the whole display/screen.

Challenge: The case is that the cursor is off when filling in the web chats input fields. The off'ness seems to be coherent with how far down on the modal the input field is. The problem is experienced in Safari, but also in other browsers like Opera and Chrome.

This works fine on Android devices, and in my opinion it's an iOS-bug that appeared in an iOS-update some time during the last six months because it hasn't always been like this.

Question: The issue is discussed in other forums, and there are some suggested workarounds. However, I'm surprised this is not yet prioritized to be fixed by Apple since I would think it affects many users. I just updated my iPhone 6 Plus to version 11.2.6, without it solving the problem.

Not sure if I explained this well, but please advice. Will there be a fix, or do we need to look at the suggested workarounds (none of those I have read about seem to be without complications for us).