Web pages are not formatted correctly, and/or images are not displaying on web pages.
This issue occurs when SSL intercept is enabled, and to allowed sites. For example: https://www.facebook.com.
The landing page will display correctly, but after logging into site the pages show only text, and the page format is incorrect.
This is a result of images and style sheets being hosted on other domains/web servers which are being blocked, by either built in or custom policy.
In order to display the pages correctly, add the names of the servers hosting the images and style sheets to the allowed domains list. For this https://www.facebook.com example, add these hosts to allowed domains list:
akamaihd.net
fbcdn.net
This also apply s to other HTTPS sites that follow the same pattern.