Final end of the chapter on the mystery of twisting lower wishbones (a-arms). JB (and others) were right. It was a bent vertical link (upright). I bought a new one for the right side from RD Enterprises, removed the old upright and installed the new one. No twisting of wishbones!
The first photo is of the new upright installed without the stub axle bolted on. The second photo is of the old upright with the new upright behind it. You can clearly see it was bent.
I had two right side uprights so I put them next to each other ( the third and fourth photos). Amazing, one upright is bent at the threaded end and the other upright is bent at the top end. Two bent right side uprights.......and they were from separate cars.
Prepping and painting the new upright for installation. And now I know that the lower a-arms don't have trailing and leading parts (just the uppers do).
Learned something new from this experience.