I have been trying to update the client tag through workflows. Set up is as follows:

Opportunity hits specific stage>Update Tag on Opportunity

When Tag is Updated to Specific Tag on Opporunity>Update Checkbox Field on Client 

When Checkbox is selected on Client>Update Tag to Specific Tag

It works up until the last workflow. This workflow will not add the tag when the system updates the check box. If I update the check box manually the tag will be added. Not sure how to have the workflow recognize the system update as well.