I’m not sure if this is a bug or by design. The Ample J bass VST accepts input an octave above normal bass range. I added a 4-string bass guitar to the score, routed it to the VST then went into Library → Instruments and see that instrument with the “(in score)” prefix. I then just change the transposition from C3 to C4 and click OK - no sound. Go back to Play and the instrument is de-coupled from the VST.
Bug or Design?
Based on the feedback to my report here:
I suppose everyone here except me do not think it is a bug. Somebody even questions how this could be fixed.
Almost… same behavior, different cause. When changing instruments in setup mode, I would expect playback to be affected - somehow. Whether the result is expected or a bug, well, I guess it depends on the situation. In my case, I was changing an instrument attribute not a full-blown instrument change. Perhaps under the covers, Dorico treats editing instrument attributes as actually changing instruments - it sure seems that way.
In any case, I consider this a bug unless someone can explain the design choice that motivated this implementation.