Instruments in score do not appear in Stage list

Hello. I am trying to use Stage for the first time. I have successfully added three of the four instruments in my ensemble called 88 Strings, but when I try to add the harp that is in my score, it does not appear in the available instruments list. See attached screenshots

Is that custom instrument saved as default in your user library?

The custom instrument was not saved. I saved it as default, restarted Dorico, and the instrument still does not appear as available in the Stages list.

Can you do Help > Create Diagnostic Report, which will create a zip file that includes your user library (along with other files) and attach it here?

Thank you Daniel. Attached is the diagnostic report.

Dorico Diagnostics.zip (1.6 MB)