It is normal for the AirRam. Every vac has a belt to rotate the brush, which has to go somewhere.
On most vacs it is on one side, so you don't get edge cleaning on that side.
The AirRam puts the belt in the middle, so you get edge cleaning on both sides. However, this then leaves an unvacced trail about 2 inches wide right in the middle, but it only takes a few seconds extra to go over this bit.
Most of the time you move the vac back and for anyway, so it gets done without even thinking about it. I don't know anyone who just pushes their vac in a straight line from one end of the room to the other, then does the same on the way back, like ploughing a field.