Interesting. I never knew about that keystroke in Finale. I'm in my usual Page View now and that only moves to the next page (and as expected, ctl-shift-D increments the page in the reverse direction). In Scroll View, it does jump to the end of the piece.

TBH, I haven't seen an END key on a Mac or Mac keyboard in many years. There are keystrokes to accomplish that but I never remember them. But while not useful for you, if you're in Scroll View it could potentially be quite useful to jump to the last measure especially if you're not done with a piece and want to get to the end to add more notes. Of course, I've always found the right-end arrow at the bottom of the window to be more intuitive but if you don't like to mouse and prefer a keystroke, I suppose ctl-D could be helpful.

In terms of getting rid of it, there is a way in macOS to remap certain application-specific keystrokes. I've done it but always need a cheat sheet since it's not entirely intuitive. Here is one source that may be helpful. 

The following is very old Mac OS news.

Many of the ordinary keys on the computer keyboard are mapped to keyboard combinations of the form

{control - Letter key}.

You can try holding down the control key, and then hit various letter keys - and see what happens.

As a consequence I generally do not let my own, custom keyboard combinations have the form {control - Letter key}.

If you create an app specific keyboard shortcut for CTRL+D in the Mac OS Keyboard pane of System Preferences and assign it to a Finale menu item, the new keyboard shortcut will replace the undocumented Finale keyboard shortcut and stop your score from bouncing around.

Assign the Finale menu item "Bring All to Front" (spelling must be exactly as quoted here) to this shortcut. All it will do is bring any/all Finale windows to the front of any other running application windows.

After some experimenting, it appears this type of Mac OS app specific shortcut can override the original Finale app shortcut only if it successfully finds and executes an existing Finale menu command. Using a dummy menu item or random text does not allow the new shortcut to replace the original shortcut. The Finale menu item, "Bring All to Front", located under the "Window" menu, appears to always remain selectable, regardless of a user's editing state and hopefully won't interrupt your workflow.

If you have multiple versions of Finale, i.e. Finale 25, Finale 26.3, 27, etc... you will need to add additional app shortcuts for each version of Finale you are using. This type of Mac OS shortcut appears to be linked to the application file name of the various versions of Finale you might have in your applications folder.