Have you created some sort of link between the two files? How did you make the copy?

I just did right click 'copy' and and right click 'paste'.  Is there another way to do it?

Is there a chance you could have clicked on 'Paste Shortcut' instead?

I have the database saved on my desktop and was copying and pasting the icon.  Thinking that might be a shortcut I tried copying the file while in the file explorer and copied it to my documents file - I did a lesson and closed the desk top file and opened the file from documents and the changes were made in that file as well.
I thought if you changed the file name it became a different file.....

I figured out what the problem was - the folder I have the file in was being backed up in One Drive - once I stopped backing up that folder and made a copy of the database - the change I made in the copy was not made in the original file.