The Collection Nodes are available for all workflow types in the Modeler Toolbox under Change Requests Custom. When using a Collection Node in a workflow, it is not running the specified collector, although the workflow completes successfully and appears to be selected. Other instances may work fine. You can see the Application and Collector are specified in the workflows's Activity Node Properties. Notice the display background for the collector specified in the workflow Collection Node is gray.
When the background is gray for the collector, it is really not selected. A warning message is being implemented for future releases.
This is a bug reported in engineering ticket ACM-74833 to be fixed in a future release.
In the workflow editor, select the collect node that is not being collected. Under the Activity Node Properties, expand the definition section and use your mouse to select the Collector. The background should change from gray to black. Save the workflow. The collector should now run when the workflow collect node is executed.