Don't know about a 'slope switch' but it might be getting flooded or getting oil in the intake at a high angle.

Maybe-when the machine is driven on a side slope or hill, your butt is lifting up just enough to allow the seat safety switch to shut it down. Someting to think about---

Okay, there is a safety seat switch on the new models and when you are on a slope and shift your weight over to the side it shuts off the engine.

Solution either jump the switch, or make sure enough of your weight is still on the seat to keep the switch alive.

Thanks guys