What steps will reproduce the problem?
(1) Create 3 input fields inside of an iFrame.
(2) Give focus to first field.
(3) Press arrow down button to give focus to the next field.
(4) At this point the up arrow button on the on screen keyboard is disabled, meaning that you cannot go back to the first field unless you tap on the first field directly.
(5) If you go to the last field, the down arrow is still enabled even though there are no more fields below it.

What is the expected output?
The focus arrows should become enabled/disabled based on which fields are available.

What do you see instead?
The focus arrows never appear to refresh based on which one currently has focus.

Please provide any additional information below.
Issue happens on all iPhones we have available (iPhone 6 Plus and 8).
Running iOS version 12.01
Running Chrome for iOS v68 and v70.
The issue does NOT happen in Safari for iOS.