2012 model having this gear jerk....! Very surprising.
This gear jerk is fault in the gear box or the gear box foundation is broken (too early to break though). I suspect gear issue, and you must show the car to dealer and ask them to fix this under warranty, hope you still have the dealers warranty, by getting car serviced from them. Above 100 kmph speed car runs on top gear and need not to shift up or down and thats why no jerk is felt. From 0-100 car shift 3-4 gears and thats why with every shift or downshift you feel the jerk.