Hi, I was faced with this bug also.
Enviroment:
- iPhone SE, iOS 11.1.1(15B150)
- Chrome 62.0.3202.70

To reproduce this bug you should have an input field with email type.
Steps to reproduce: 
- Start fill input with email address
- After few symbols typed Chrome will suggest you to autofill the input with known email
- Tap on the suggestion to apply it

Expected result: I can see the autofilled form and I can get the same value using Javascript
Current result: I can see the autofilled form, but when I tries to get this value, I can see just few letters which I typed before the input was autofilled

Wasn't tested on inputs with other types

The problem here is that input elements are not inside <form> tag, which is not supported yet on IOS. 
Support of no <form> forms is on my task list for M-66.