Issue with instrument playing in Notation program

Im trying out a sound library in a Notation program and one of the instruments will ONLY play if its selected (highlighted) in the score. When its not selected everything else still plays fine, but not this one instrument

I know this is kind of vague and strnge and I apologize for that–any ideas what in this instruments sound set (which controls how it plays) that might be causing this?

Thanks for any and all help! Bob