Editing/highlighting functions get lost when QMAKE_CXXFLAG is defined in certain way

Qt Creator looses editing functionality such as prediction and highlighting when the following line is added to .pro.

QMAKE_CXXFLAGS += -D MODULE_NAME=\\\"$${TARGET}$${MY_MODULE}\\\"

Also Qt Creator shows Issues

and warnings.

No highliging in mainwindow.cpp

How to reproduce :
Use Qt Application example and add the following to .pro and then Run qmake

QMAKE_CXXFLAGS += -D MODULE_NAME=\\\"$${TARGET}$${MY_MODULE}\\\"