After installing K2 Five (5.0) September 2018 Cumulative Update Fix Pack 6, multiple rows of data return instead of just one value. This occurs when your workflow is configured to return the destination user’s name that approved a task, by creating a reference in the workflow using the Activity Instance Destination SmartObject and passing the folio and activity display names to the reference.
This issue was introduced by a fix made in K2 Five (5.0) September 2018 Cumulative Update Fix Pack 6. More information on the fix can be found here.
Update your workflow by following the steps below:
Note the same issue may occur in other versions of K2 Five, you can apply the same workaround to these versions.