user Feedback error message "the field with the name return is not allowed

Summary:

in the Visual flow designer when i add the getuserFeedback component at the end which has a transition set to End Flow(implicit) I see an error on the flow.

Content (please ensure you mask any confidential information):

I am trying to add a getuserFeedback to the visual Flow Designer in a simple example. I add it to the end of the flow with a transition of End Flow (implicit), but I then see a red warning appear in the flow. Under the findings drop down it states - The Field with the name 'return' is not allowed in the flow 'null.transitions'