Reply to FX 3 and 4 for Kontrol S2/Maschine

I'm aware that you can use custom mappings for Kontrol S2 to control FX 3 and 4 from the S2 hardware itself.
I have a Maschine and I mapped my FX 3 and 4 to the Maschine. When I try to use FX 3 and 4 on the Maschine, the effects are shown on the Traktor interface as working with all the corresponding lights on.
However, I cannot hear the effects actually taking place. FX 1 and 2 work perfectly through the Maschine but when I try to use FX 3 and 4, the results are unavailable.

Anyone know how to get around this?