Are you using Windows Finale or Mac Finale?

If I understand you correctly:

1) When you go to

Document menu > Edit Part > …

you see the linked part displayed correctly on the screen, with all dynamic markings - right?

2) When you go to

File menu > Extract Parts…

you get a new Finale document of that part only, and no dynamic markings - right?

I do not understand why you extract parts.

It is seldom necessary.

as a matter of fact I have not extracted parts for years.

Why can you not just use the (correctly displaying) linked parts instead?

You can print the linked parts, and also export them as PDF files.