Connections type doesn't work in qmltc'ed app

Build attached code and start executable. Clicking on rotating rectangle should stop rotation, but it doesn't. It doesn't work with the Connections type in compiled QML, but works for instance when using the qml runtime:

qml window.qml

or when using the onClicked handler directly in the MouseArea or with an explicit connect (marea.onClicked.connect(conn.onClicked).

Besides that, the build system feels awkward (line "target_include_directories(exeqml PRIVATE ${PROJECT_BINARY_DIR}/.qmltc/${CPP_MODULE})" shouldn't be needed). Am I doing something wrong?