QML app not painted on update if screen is locked

Application window is not painted when updated if screen is locked. When running the test application, after clicking the button, the text property of the button should change to " " after 70 seconds. If this happens when the screen is locking, it won't be painted even though value of property is updated.

Way to reproduce:

1) Set "switch the monitor off after 1 Minute of inactivity" from Windows settings.
2) Build and run the example project with Qt 5.15.5
3) In the application press the button to start the timer
4) Immediately after pressing the button lock the windows screen by pressing Ctrl+Alt+Delete and select lock
5) Wait until monitor is switching off by windows
6) QML timer is triggered to clear the text

What is expected:
Text of the button is changed to "" after screen opens again.

How it behaves with 5.15.5:
The text is unchanged, unless application window is updated again.