I still get that abrupt reverse 'lunge' on rare occasions. Maybe once or twice a year. It's when I shift from drive to reverse.
Although I stop completely before shifting out of drive, and I pause for a second in neutral, I suspect its caused by the gearbox not being in the low range.
The cvt switches ratios at a stop, takes a few seconds. You can feel the shift. That could be causing what I'm feeling. I need to stop and wait 3 or 4 seconds for that gearbox to drop into low.
Just a guess.