What is the reason a random string is appearing on my Customer Portal page in staging but not development?

Environment:

Customer Portal
Oracle B2C Service

Issue:

A string like this appears on our end user pages:

Resolution:

This is a standard placeholder for the insertion of runtime header content. This string does not show in the Development area of your site because the code has not been optimized. It will only be displayed in the Staging and Production areas, so if you are seeing this string during development, do not promote to Production. 

If this error is occurring on a page with code that was not provided by Oracle B2C Service, you will need to debug your code for errors. In the instance that you are unable to troubleshoot your code you may reach out to your Sales Account Manager about scheduling an Oracle Professional Services engagement.

If the custom code you are experiencing this problem with was provided by Oracle Consulting Services, submit a service request to Ask Technical Support.

Do understand that when optimizing ; there are certain keywords that are not usable in the Customer Portal.  These can be found via the answer here:Reserved words in Oracle B2C Service

Cause:

This behavior usually indicates a coding error with a custom widget causing the PHP replacement to fail. One common cause of this behavior is using the wrong commenting convention in a file. For instance, a JavaScript logic file cannot use <!-- HTML comment types --> and must use /* JavaScript comment types */ and using the wrong type may cause this behavior.