qt_generate_foreign_qml_types fails with Q_ENUM_NS

[22/40] Automatic QML type registration for target ui_qml
Warning: Refusing to generate non-lowercase name "Flupp" for unknown foreign type

[27/40] Building CXX object CMakeFiles/ui_qml.dir/ui_base_ui_qml.cpp.o
FAILED: CMakeFiles/ui_qml.dir/ui_base_ui_qml.cpp.o 
/usr/bin/c++ -DQT_CORE_LIB -DQT_NETWORK_LIB -DQT_NO_DEBUG -DQT_QMLINTEGRATION_LIB -DQT_QML_LIB -I/tmp/p -I/home/andre/hg/QmlDummy -I/tmp/p/ui_qml_autogen/include -I/usr/include/qt6/QtQml/6.6.2 -I/usr/include/qt6/QtQml/6.6.2/QtQml -I/usr/include/qt6/QtCore/6.6.2 -I/usr/include/qt6/QtCore/6.6.2/QtCore -isystem /usr/include/qt6/QtCore -isystem /usr/include/qt6 -isystem /usr/lib/qt6/mkspecs/linux-g++ -isystem /usr/include/qt6/QtQml -isystem /usr/include/qt6/QtQmlIntegration -isystem /usr/include/qt6/QtNetwork -mno-direct-extern-access -MD -MT CMakeFiles/ui_qml.dir/ui_base_ui_qml.cpp.o -MF CMakeFiles/ui_qml.dir/ui_base_ui_qml.cpp.o.d -o CMakeFiles/ui_qml.dir/ui_base_ui_qml.cpp.o -c /tmp/p/ui_base_ui_qml.cpp
In file included from /usr/include/qt6/QtQml/qqml.h:9,
                 from /tmp/p/ui_base_ui_qml.h:3,
                 from /tmp/p/ui_base_ui_qml.cpp:1:
/tmp/p/ui_base_ui_qml.h:9:17: error: ‘A’ does not name a type
    9 |     QML_FOREIGN(A)
      |                 ^
[28/40] Building CXX object CMakeFiles/ui_qml.dir/ui_qml_qmltyperegistrations.cpp.o
FAILED: CMakeFiles/ui_qml.dir/ui_qml_qmltyperegistrations.cpp.o 
/usr/bin/c++ -DQT_CORE_LIB -DQT_NETWORK_LIB -DQT_NO_DEBUG -DQT_QMLINTEGRATION_LIB -DQT_QML_LIB -I/tmp/p -I/home/andre/hg/QmlDummy -I/tmp/p/ui_qml_autogen/include -I/usr/include/qt6/QtQml/6.6.2 -I/usr/include/qt6/QtQml/6.6.2/QtQml -I/usr/include/qt6/QtCore/6.6.2 -I/usr/include/qt6/QtCore/6.6.2/QtCore -isystem /usr/include/qt6/QtCore -isystem /usr/include/qt6 -isystem /usr/lib/qt6/mkspecs/linux-g++ -isystem /usr/include/qt6/QtQml -isystem /usr/include/qt6/QtQmlIntegration -isystem /usr/include/qt6/QtNetwork -mno-direct-extern-access -MD -MT CMakeFiles/ui_qml.dir/ui_qml_qmltyperegistrations.cpp.o -MF CMakeFiles/ui_qml.dir/ui_qml_qmltyperegistrations.cpp.o.d -o CMakeFiles/ui_qml.dir/ui_qml_qmltyperegistrations.cpp.o -c /tmp/p/ui_qml_qmltyperegistrations.cpp
In file included from /usr/include/qt6/QtQml/qqml.h:9,
                 from /tmp/p/ui_qml_qmltyperegistrations.cpp:7:
/tmp/p/ui_base_ui_qml.h:9:17: error: ‘A’ does not name a type
    9 |     QML_FOREIGN(A)
      |                 ^
[30/40] Building CXX object CMakeFiles/ui_qmlplugin.dir/ui_qmlplugin_StuffPlugin.cpp.o
ninja: build stopped: subcommand failed.