I continue to receive the following message when I attempt to check for completion of the Automating Processes with Workflow Trailhead module:
Challenge not yet complete... here's what's wrong: 
The 'Set Case to Escalated' Workflow field update action was not found.

I even tested and confirmed that the workflow rule works and all of the required actions have been created and completed per the instructions of the module. A bug on the challenge verification perhaps?