Front Seat Power Adjust problems of the 2003 Infiniti FX35

The seats on this and two other Fx35's we own from Infiniti "rock" back and forth while driving. The seat position is not stable. This is also widely reported with the g35 and Infiniti cannot fix it. I believe it to be critically dangerous. The sway back to front is sudden and significant enough to jar the driver causing loss of control. My seat literally rocks about 1/3" back and forth like a rocking chair. We have another one that does exactly the same thing. In the snow I can imagine the sudden sway to be significant enough that a driver may lose control. I also wonder about crash durability. As you know any increased tolerance would allow an impact to cause more damage to the seat frame of the driver, possibly causing the seat to dislodge.