When opening a custom ASP page, the page does not load fully and when the page is resized, the vertical scroll bar is missing.
In one particular instance there was a malfunctioning custom content script on the screen the customer was navigating to.
This script was referencing a field that didn't exist on that screen. When this script was removed the issue was no longer reproducible.
To help prevent custom content issues, all custom content should be tested thoroughly in multiple browsers and browser versions to ensure that no issues have been introduced into the system.