you need to refresh the parent object so that the reference selctors Data source Micro flow will be triggered to get the newly added obj
Whenever you need to get a new element when you triggered the reference selector without leaving the page is that you need add the refresh in client to the first object of the microflow or refresh the parent object of the microflow, so that the selectors triggers the microflow which is a data source of the element which is to be added newly.