Strange Pedal Tone When Accents Are Added

I’m working a piece for trombone and piano. Whenever I add an accent to a note in the trombone part, Dorico plays the pitch I wrote, but also a pitch two octaves lower. When I remove the accent the low note remains. The piano part is fine. Ideas, please?

It sounds like you’re using a VST that uses key switches but haven’t set up your expression map correctly.

Yes, if you’ve changed the sound in Play mode, you also need to review the expression map that’s chosen in the Endpoint Setup dialog. If you’re no longer using the HSO trombone sound, you will need to choose a different expression map, probably the ‘Default’ one.