Hi and welcome. We will need more info to do anything but make blind guesses.

https://makemusic.zendesk.com/hc/en-us/community/posts/215729367-General-Discussion-House-Rules 

So sorry. I am using an iMac running Monterey with an i5 processor and 32Gb RAM. I am running Finale V27.1.0.277. I am using GPO5. The issue is as I stated earlier. My strings suddenly lose volume to the point where they are barely heard in measure 180 of a piece I am working on. I am not trying to "replicate" the issue, as it happened without me doing anything. I have tried everything I can think of and have searched the net for answers. So far there are none. Does this help?

Try setting HP to None. Play it back, stop, and then turn HP back on.

You might also try:

Select All > Clear Selected Items… 

In the next screen, first click None, and then click MIDI Data, and OK

Thanks to everyone who responded. I tried turning off/on HP and that action caused a new problem. When HP is set to "None" my first violin track plays pizz without being marked to do so! And of course, when I switch it back to "Romantic" the violins play correctly, but it doesn't fix the volume issue. I have cleared MIDI Data several times and that doesn't work. 

Question: since I experienced an oddity with my first violins after switching HP off, could it be my Finale or GPO5 is corrupted? Maybe I should uninstall and reinstall Finale & GPO5. Thoughts?

I think it is still an HP problem. This is an issue that MM knew about when releasing Finale v27. They are supposed to be working on a update to HP. It has something to do with how 27 interprets SMUFL.  If you use legacy fonts does this happen? Perhaps you have an olderd score not created in 27 . Does it playback correctly?

Clearing the midi data won't fix this.

Doug,

Try one of the other HP preferences just for fun. Does it make any difference?

Thanks for your help Ernest! I changed fonts, changed HP styles and neither of them had an effect. I created the file in V27. I have also tried switching to East/West samples, but that introduces new problems. It is obvious MM has issues they should have addressed before releasing an update. 

Ok, this is wonderful. None of the excellent suggestions I have received have worked. However, I saw on Ernest's profile that he uses NotePerformer so I downloaded the trial version and gave it a go. What amazing software! Not only did it fix the problem, but it also opened a new world of possibilities for me. I may cancel my subscription to East/West!

Thanks everyone!

I'm a NptePerformer convert, too. I don't think that the VIs are superior to others that I own but its AI engine saves me a lot of time and it only costs $129. I like that!