A limited-slip diff will do the same thing, it really only works when both tires have somewhat similar traction. If one has much less than the other, it will get away and spin just like the diff were open.
Any 4WD without lockers or some sort of torque management system is at best a 2WD when traction is scarce. One front and one rear wheel will spin while the other two do nothing. It's not at all "dumb" it's the way it works.
Brent
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