Non Modal dialog popsup with QPrinter involvement

In Qt6 when QPrinter is used, a message popups: "Please wait for printer connection or cancel connection."
This is not the modal dialog and you can not only push the cancel button but you can interact with the entire application and even close it, This is very dangerous, because the object, to which the slot belongs to might be destroyed before the QPrinter object is initialized. 

attached tiny example can show the issue. Just Hit Print Button.

In Qt5 the whole application were blocked for couple of seconds.