Slope landing limits are developed by the manufacturer and will take this sort of thing into account. The certification authority will also test it to make sure it's OK.
I know of one manufacturer who published a slope landing limit of 3 degrees - which of course is pretty useless. Turns out they meant you could land on this much slope, with 40 knots of wind from the worst side, with the worst lateral CG, and still be able to stop and start the rotors safely. I recently told them they need to reconsider their method of testing and demonstrating limitations, as there is no requirement to shut down....