<VV> Early halfshaft wear mystery

[Doug Mackintosh]

Today on my way to work, after a swift right sweeper and just as I straightened back out I heard a squealing noise from the Left rear wheel area. At first I thought the tire was rubbing, but I could find nothing close. The noise continued intermittantly, seemingly making noise on left turns (or when there was thrust that direction) and going away if I turned right. When I got home I inspected the axle and found a shiny worn band about 3/8 inch wide on the axle shaft. The worn area is at the left (outer) end of the opening in the rear of the A-arm for the axle exit. See the photo here:
 
http://farm4.static.flickr.com/3356/3471808313_ce02e76aaf_m.jpg
 
It looks like recent wear, almost like it was turned on a lathe. But I could not find any corresponding shiny spot on the A-arm. I have the axle out now, and partially disassembled. I can't figure out how it got the shiny band. There does not seem to be enough slop in the bearing or U-joints to actually allow contact. 
 
Has anyone seen this before, or have any ideas I have not thought of?
 
Thanks!

-- Doug Mackintosh
Corsa member since 1996
Corsa/NC member since 1996, Virtual Vairs member
Corvair owner 1969-1971 and 1996-on