Thank you for your response.
Yeah, I tore it down to the swing arm three times I and don't have a single part left over.
I suspected maybe the pivot arm had a bad bushing or something. I can't find anything "wrong".
It's got me baffled.
I've got the tire marked up with a tire crayon and I'll get to ride later. If the crayon gets rubbed off, then more head scratching.
Here's some more pics: