I used to go numb with certain saddle set ups occasionally. If I did, it scared me, so I got off right away and adjusted the seat angle or took a long break.
Don’t believe that tilting your seat back, so it is flat, is going to solve the numbness issue, like others seem to believe. It is dependent on the rider. When I tilt my seat back too far, I go numb (doesnt matter which seat it is). I have to make sure it is tilted forward a little. This was especially the case with the older KH seat tilted back.
My new set up does not cause me to go numb, and it is basically a bulkier version of the new KH freeride saddle. Try buying the new KH freeride, it will make a world of a difference. It isn’t as curved and it has a cutout in the center of the seat, which prevents you from going numb.
I personally wouldn’t mess around with going numb at all. It should not be accepted as inherent in cycling, and you should get off right away if you start to notice that you are going numb.