Surely the bearing failed first?, so the inner race turned on the shaft, tightening the nut and shearing the pin? A bit of extra torque on the nut would not make any difference to the bearing clearance unless it deformed the inner races, which is unlikely. As above, the clearance is set by the machining process, the nut only has to apply enough pressure to hold the inner races firmly together.
It was the pin and nut on the other end - not the spider/duplex bearing end - that failed and the excessive Tq was on the spider end nut which didn't fail and the split pin was intact. How did the excess Tq happen?
Aucky - just like the 139.