So with a sway bar and the heaviest spring, I stand by my original recommendation of the softer front spring or go softer all around. Its very hard in offroad to theorize some things because you could be "rut" rolling more than traction rolling, hitting an uneven part of the ground that is causing the tires to grab hard, it happens to us in onroad too, you can hit a bump or a seam in the carpet and it will grab, even if the setup is actually on point.