carpediemracing has it right across the board (expect maybe the catastrophic results).
Then you haven't any of the recent threads on [soaking chains]. Where there still isn't any general agreement.
Lack of consensus does not make the assertion wrong.
Ever wonder why Shimano recommends against removing the chain for soaking ?
The bushings go around in circles. All the interior surfaces will be loaded the same. I cannot see how there would have more "wear" in one direction vs. the other.
The rollers are free to go around; the pins and plates aren't. Further, because the rollers
can go around doesn't mean that they do.
We did some geometry calculations on this in an earlier thread attempting to determine what the effect would be. [Someone do a search.] Yes there is more wear to one side of the link centerline.