When you create a stage transition rule, you select a User credited with this action. This user’s name appears in a candidate’s Activity Feed as the person who completed the transition rule’s automatic action.
In the Activity Feed shown below, Geri Kellman is the User credited with this action.
However, if an auto-advance application rule is also configured to move candidates into the stage, both the sender of the email and the user credited with the action (as shown in the candidate’s Activity Feed) is the person who configured the auto-advance application rule.
In summary, the selection you make for User credited with this action when configuring a stage transition rule applies only when the candidate is moved to the stage manually. The user's name will not appear in the Activity Feed if the candidate advances to the stage using an auto-advance application rule.