Enabling CMAKE_AUTORCC also enables CMAKE_AUTOMOC even if it's disabled

Question

In CMakeLists.txt I explicitely set:

set(CMAKE_AUTOMOC OFF)
set(CMAKE_AUTORCC ON)

However, I still get automoc project generated which is empty. If not using AUTORCC, there is no automoc project.

Does anybody know why it behaves like this and whether I can switch it off completely?

We are using CMake 3.4, Qt 5.4, MS Visual Studio 2012.