STEPS TO REPRODUCE
1. Build and run the attached app.
2. Attach an Italian keyboard.
3. Switch to the Italian input source / keyboard layout in the OS.
4. Click in the widget in the middle of the window.
5. Press é (Shift+è).

EXPECTED: The keyboard shortcut is displayed as É.
ACTUAL: The keyboard shortcut is displayed as Shift+É.

This key doesn't exist, so if you store this and later use it to set up the key sequence for a shortcut, it won't work.

It looks as though QKeySequenceEditPrivate::translateModifiers is making an assumption about the shift key only 'counting' when it is not used to produce a symbol, which is not true for some international keyboard layouts. Italian has another example too: ç (Shift-ò)