Symptoms

Is there a way within K2 Workspace that when someone changes the default version for a process that this is somehow tracked within K2 somewhere? This would be advantageous when trying to track down issues with processes. We just ran across this and we're not sure how long the default version was incorrectly set.
 

Diagnoses

There is not a specific report or smartobject this checks this. However, with a little detective work, you can get the information you are looking for.
 

Resolution

In the System SmartObjects under Reports there is the Workflow Instance SmartObject. I would recommend executing this, and shows you a great overview of when processes were started and when the version that was used to start it. I would check when the version was changed and track the versioning from here.