I had a nearly identical problem with my 354LE. I was certain it was a defect, but now I'm not so sure. I think a slightly low oil level in the axle housing will starve that bearing of lubrication because of its height above the housing. Anyway, I regularly check that oil level now, and keep it well filled – so far, so good. I also make sure the venting tube on the filler cap is clear.
Good Luck, Mike