CXX.FUNC.T2OLE.RETURN
Do not call T2OLE or OLE2CT within a return statement.
Do not use the results of a T2OLE or OLE2CT conversion as a return value of a function, unless the return value is actually a copy of the string.
Vulnerability and risk
For more information see MSDN Technical Note 59.
Mitigation and prevention
Consider storing the return of the macro in a local variable and then returning that instead.