The torque on the castellated nut retaining the shaft in the duplex bearing has no effect on the function of the bearing. It's an opposed angular contact set-up, with solid inner races. The torque applied to the nut will have no effect whatsoever on the internal bearing clearances. Any over-torque of the nut would serve only to stress the shaft, most likely in the waisted section immediately below the thread, and that doesn't seem to have occurred give the photos above.