Does anyone else's driver's seat do it? Normally, I can feel the slight rock in slow, stop-and-go traffic when coming to a complete stop. Entire seat rocks slightly. I can also get it to rock just by rocking in it. Feels like the mounting somewhere is a bit loose. Brought it to the dealer; dealer said they tightened it a bit and aligned. It's still the same. Doesn't seem that the tracks bolting it to the floor are the problem. I ran it through all the power settings and it still rocks. Is this normal for the power seat mechanism?