Premature wheel bearing failures.

Whenever I replace those bearings I change the grease in them to what I know works. Some of the greases I have taken out "seem" like pure junk. Honestly some have looked like Vaseline.
Yours looks like the grease went away and the parts were metal on metal, which doesn't survive long.
If the spindle loses torque, the bearings will separate, the extra clearance will allow the stub axle to migrate upwards and wear out the upper seal, and lift off the lower seal. this will allow water in and grease out. Those nuts have a specific torque spec that crushes everything together.It stretches the spindle and makes it act like a spring to maintain the torque. The whole deal is too small for the application, IMO, and depends on everything being just right.
The grease is not just a lube, it is also the coolant. With the grease going, going, gone, catastrophic failure is guaranteed.
If your spindle is bent, even a couple of thousands, accurate torque cannot be maintained, but worse is, as it rotates a couple of rollers are going to be under extreme pressure, squeezing out the lube,and producing heat.

Everything in that type of hub depends on the grease doing its job and staying in there, and transferring it's heat to the hub. That also means the brake-rotor better not be cooking the grease.

Best of luck on your next install