Unable to Transition work item because required field is empty

[Joel Mark]

I'm attempting to create an automation that moves a story ticket to an "On Hold" status when its subtask is also put on hold. However, the workflow dictates that a particular field in the transition screen can not be empty. To make sure the field isn't empty, I've added that the required field be set during the transition. However, the automation is failing because it still reads the field as empty. 

I thought that maybe the automations were firing out of order so I instead added an action to update the field before the transition. No dice. 

I then updated it so that the field was updated, the work item was re-fetched, then it was transitioned. No dice. 

What am I missing here? Why isn't the field being set? or why is is being overwritten with null?

[Mohanraj Thangamuthu]

Hello, Good day. This is Team managed project or company managed project?. One possible reason there are two fields with same name. Could you upload a screenshot of error from automation rule?. Thanks