Where did you store the file she sent?
Was the filename this week different to the filename last week?
Did you close the file after she sent the file last week, or has it been knocking around in the background (or minimised) all week?
Did you double check that the file she sent today is actually the most recent version she’s looking at?
Has she manually saved the file at any point in the past week (genuine question - I’ve just opened a Garageband file from a colleague and it asked me if I wanted to use the saved version, from three days ago, or the Autosave version from 10 minutes ago).
I’d be extremely surprised if this were actually a Dorico problem.
I’ll just throw in something that caught me out recently.
If you have a Dorico project that is already open, attempting to open another file with the same name doesn’t open the new file, it just displays the already open file.
This is more confusing if you have several windows or project open, if Dorico changes the active window and that makes you think it has opened a new file.
As pianoleo said, close everything and then check the location and time the stamp on the file you are opening.
RESOLVED: It turns out the student had indeed sent a different version of the file. I don’t yet understand how it happened and how she figured it out, but somehow she ended up working on a version of the file stored in the Dorico Backups folder, not the one in the folder she had created for Dorico files.
Sorry for the false alarm and thanks for the help!