My SRAM rear derailleur (Rival 22 circa 2016) has a non parallel movement. When it is in the lowest gear, the cage and pulley sprockets align with the cassette sprockets, but when it's in the highest gear, it is very miss aligned.
I measured the distance between the pivot points. I got 48mm and 49mm, which would explain the non parallel movement.
Question 1: What was the design reason for this?
Question 2: Do I need to get the alignment of the derailleur hanger checked? The gears shift easily. I'm just worried about drive chain efficiency.