I had a similar issue and the problem was that my dependencies were messed up. Make sure you have all dependencies downloaded including the files in UE4\Engine\Source\ThirdParty\Windows\DirectX\Lib. The XInput module links against XInput.lib and that’s what defines the actuall XInput DLL being used. If you miss xinput.lib in the folder I mentioned above then the linker might find it somewhere else (DirectX SDK).