Substitution Variables Screen Sometimes Does Not Render

Summary:

Have noticed sometimes the substitution variables and data maps screens will not render for some users for a time.

Content (please ensure you mask any confidential information):

This happens for different users at different times irregularly with different browsers. Rebooting the browser and/or clearing cache does not help. Then this issue goes away. Has anyone noticed this?

Version (include the version you are using, if applicable):

PBCS

Code Snippet (add any code snippets that support your topic, if applicable):