QML Singleton does not work if not in root folder on MacOS

When QML Singleton file is not located in root of the project, there is following error when running the application:

qrc:/SingletonTest/qml/main.qml:14: TypeError: Colors was a singleton at compile time, but is not a singleton anymore.

Aliasing all QML files in CMakeFiles.txt (and adopting main.cpp) fixes the issue:

set_source_files_properties(qml/main.qml PROPERTIES QT_RESOURCE_ALIAS main.qml)
set_source_files_properties(qml/Colors.qml PROPERTIES QT_RESOURCE_ALIAS Colors.qml)

But these aliases must be created for all files in the module.

Minimal example is attached.