Noteperformer does not save instrument channel mute

I am currently doing some orchestrations from piano works.
I input the music to a piano grand staff.
Then I add the staves for instruments as needed and proceed to copy the parts out from the piano. At this stage I mute the piano output on the Noteperformer plugin.
When I save the file, then open it later, the piano is unmuted in the Noteperformer mixer every time.

This is with Dorico 4 and Noteperformer 3.

An alternative to muting the piano is to select a measure or so (more than one note) of the instruments you want to hear.

what do you mean by the NotePerformer plug-in? If you mute in the NP mixer, save the file and re-open then it’s still muted on a quick test I just did. This is with the latest Dorico and NP but I’d be surprised if it would make a difference.

I mean just what I described.
When I open the Noteperformer plugin there is a mixer. When I mute the piano on that mixer, save the Dorico file, close it, then reopen it, the piano is not muted.
As a workaround, I have unloaded Noteperformer from the piano track in Play mode (and this setting is obviously saved correctly with the file).

Windows 10, Dorico Pro 4, Noteperformer 3

as I said, it works here so perhaps you’d like to attach a sample project to see if this can be replicated