This is not correct, but is widely circulated, repeated and believed to be true. The AWD clutch is, essentially, continuously variable, and is controlled according to a number of parameters, including gear, speed, throttle, engine load etc. In 1st gear, and somewhat in 2nd, the clutch control responds at a more rapid rate to some of these parameters than in the higher gears, but neither 1st nor 2nd will necessarily set a full-time, 100% engagement of the clutch.From what I understand, the 4EAT will shift power from all 4 wheels in 2nd gear ---> to 90% front wheels in 3rd gear.
How did you come to the conclusion that it's the AWD? Did you insert the AWD disabling fuse to see what happens with it in (and the AWD not active)?
Perhaps a more detailed description of what is happening would be helpful. How we think of a "bounce" and what you're experiencing might differ in as many ways as there are readers here.