QKeySequenceEdit shows gibberish when 'dead' keys are pressed

I did this on the Mac, but I think it will happen on Windows too.

STEPS TO REPRODUCE:
1. Build and run the attached test app.
2. Plug in a French keyboard.
3. Switch to the French input source in the OS.
4. Click on the QKeySequenceEdit in the middle of the window.
5. Enter ¨ by pressing Shift+^ (the key to the right of the P).

EXPECTED: It probably shouldn't show anything, as you can't assign a shortcut to a dead key.
ACTUAL: The shortcut widget shows a Chinese character followed by a peculiar-looking arrow.

I suspect Qt::Key_unknown needs adding to the list of early-return exceptions towards the top of QKeySequenceEdit::keyPressEvent.