What other cars have you driven? That might help us... help you. It's really hard to tell if it's normal or not with out comparison or a video.
I've driven a lot of cars (rentals) recently. New Toyotas, Hyundais, Mitsubishis ... these had traditional 4AT or 5AT... Volkswagens (both dsg and manual), a Mitsubishi Pajero 4AT ...
The fact that you are asking me this, well it kind of hints to that one should expect a Lineartronic to thump and jump more or less when moving the stick. If it didn't you'd think owners would just say "Nope, when I shift from park to reverse nothing happens at all"
This is simple, really, if you have a Lineartronic OB:
1. start the car
2. brake pedal depressed, shift from park to reverse
Q: do you feel _any_ sudden jolt like movement / car body movement? yes or no
My answer is "no" for all cars I've driven over the last few years except for this OB, which is the first Lineartronic I've driven.
The previous time I've experienced something like this was with some old manual trans cars, a long time ago. So I'm just wondering if this is a feature of Lineartronic or not.