QThreadPool keeps running decoder after QApplication isAboutToExit()

[derselbst]

 	Qt6Cored.dll!qt_message_fatal(QtMsgType __formal, const QMessageLogContext & context, const QString & message) Line 1872	C++
 	Qt6Cored.dll!QMessageLogger::fatal(const char * msg, ...) Line 882	C++
 	Qt6Guid.dll!qt_pixmap_thread_test() Line 84	C++
 	Qt6Guid.dll!QPixmap::QPixmap() Line 113	C++
 	anpv.exe!Image::setThumbnail(QImage thumb) Line 183	C++
>	anpv.exe!SmartImageDecoder::init() Line 233	C++
 	anpv.exe!SmartImageDecoder::decode(DecodingState targetState, QSize desiredResolution, QRect roiRect) Line 361	C++
 	anpv.exe!SmartImageDecoder::run() Line 327	C++
 	Qt6Cored.dll!QThreadPoolThread::run() Line 100	C++
 	Qt6Cored.dll!QThreadPrivate::start(void * arg) Line 328	C++
 	kernel32.dll!00007ffcb7137614()	Unknown
 	ntdll.dll!00007ffcb8aa26a1()	Unknown