Change Task Creator not able to change Assignee and Reviewer role in the Wizard

Version: Windchill 12.1

Use Case: I have one user not able to change the assignee or reviewer of the default task, but when he creates a new task in the CN and deletes the default one he can change the assignee and reviewer.

Description:

This is not happening for any other user. His licensing and rights have not changed. He was able to make these changes until about an hour ago.  What could be happening and what should I be looking at on his computer to fix this issue? 

We just patched our 12.1 from 12.1.2.0 to 12.1.2.9 and had to have the users clear their caches in the browser and in the embedded browser to allow attachments and resulting objects to populate the windows.