QProgressDialog cancel button is shown again after setting it to nullptr, if language is changed using QTranslator

When I create a QProgressDialog, and set the cancel button to be hidden by using 

setCancelButton(nullptr);

it will be shown again when QEvent::LanguageChange event is triggered. Using

setCancelButtonText(QString());

works fine. I checked the source code, and noticed that QProgressDialog::setCancelButtonText sets useDefaultCancelText flag to false, while QProgressDialog::setCancelButton doesn't. This flag is then used when changeEvent is triggered due to language change, and if it is true, it will create the default cancel button.