Parenthesized metronome marks visible only in score

I found this to display metronome marks in the score but hide them in the parts

So far so good, but if the metronome mark is wrapped in parentheses then the parentheses appear around the text e.g. (Allegro) in the parts. A local change in the properties has no effect.

Is there a workaround except to relinquish the parentheses totally?