The document that you have uploaded online is it through the web browser or desktop application?
When you are opening the pdf uploaded on Document Cloud, then is it opening it through chrome or via Acrobat plugin. Because when you open the pdf on web using chrome, then it uses its own pdf viewer on which Adobe doesn't have any hold.
Also, check with a different pdf if that is doing the same? Because it could be pdf specific issue because of that fonts used to create the pdf has not been embedded correctly.