Lack of coffee that morning.
Actually, it's because I didn't know better. I thought it would pile all the mud in the middle of a rut (if it dug one) thereby filling the rut back in, BUT there was a thread on which way to mount grippy tires and...I've since learned differently.
Both of the OEM
front tires are mounted on the rim the same way, so one of them is always backwards...however one is always forwards, so... I guess I should re-mount one so I can mount them both on the tractor the wrong way.