If you reference a master measure in an expression and then change the master measure's name the expression has no longer a connection to the master measure because the name does not adapt the changes automatically. Hence, you have to manually change it wherever you have used the master measure in an expression. Very time consuming and difficult to find each and every expression that contains the master measure.
It would be great if this would work like it is with fields. If fields are renamed via the script the references in the interface automatically adapt the new name and are still linked to the renamed field.