This is my first automatic car that I have purchased without intentions of flipping it, all of my previous vehicles that I have purchased were manuals for the exact same reason, modern automatics are programmed weird and have odd behavior. The torque converter creating the odd behavior is definitely a big possibility. I am glad someone else notices exactly what I am referring to, and I too have considered going to the dealer and have them check it out but I will definitely get "its normal" response. Heck, I went to the dealer with my drivers seat having the rocking issue and they told me that is normal.
My girlfriend has a 15' Jetta TSI and it too has an odd behavior when it shifts into 2nd, almost like it wants to fall on its face but then it takes off. Happens in a matter of seconds, and her 15' rental Jetta did the same thing. Really annoying.