When showing two moving averages on same graph, cannot distinguish by color

I have a measurement containing two fields, and I wish to show a moving average of each of those fields in the same panel. This works fine - except that the label for each line ( which are from different fields ) just says ‘Measurementname.moving_average’ ( i.e does not include the actual field name ), and I cannot set a different color for each line. It’s asif the label just picks up the last item in the ‘SELECT’ field, and so the coloring cannot distinguish them if the function is the same in each case. Am I missing something, or is this a bug ?