Scrub playback but.. strings are silent

The Scrub playback feature is great, but for some reason in the orchestral score I’m working on, all the strings are silent when it’s active. This is with NotePerformer 3.3. The strings are definitely there in normal playback mode… but moving the mouse over the string parts in scrub mode is silent.
Any thoughts?..

No – could you attach the project here? Cut it down to just a few bars. If you’re not sure how, look here:

Hmm. To make an example for you, I cut down to a few bars as you suggested, and saved that out as a new score. Upon quitting Dorico and restarting, loading in that cut-down score… the string scrubbing works. But it (repeatedly) doesn’t in the large score it was derived from…

OK, then by all means send me the larger version by a private message if you don’t want to post it here.