When entering characters into a html password input form field that is hosted in a QWebEngineView, the shortcut is triggered instead of consuming the character in the input field.
So no passwords can be entered that contain characters that are assigned to shortcuts.
This issue only affects password input form fields. Regular text input form fields work as expected, they consume the typed character and do not trigger the shortcut.
The issue cannot be reproduced using Qt 5.9.9 so this seems to be a regression introduced in a later Qt version. Mac OS does not seem to be affected even with Qt 5.12.6.
The attached test program demonstrates the issue. When entering "1" or "!" the registered shortcut is triggered instead of entering the given characters into the password input field. Entering the same characters into the username field works as expected.