[Trackrash]

Very common. It can be because the car is very low, there is a bent strut, or the tar crap around the upper mount is preventing the upper mount to move as far as it should.

Almost forgot, worn or loose parts such as the strut inserts, wheel bearings, ball joints, or upper mounts, can cause this.

I, and others, have enlarged the bolt holes for the upper mounts and removed the tar, to gain more adjustment.

I had the same problem after I first got my car. Took it to a "specialist" and he could not get the camber where it should be. I asked him if my struts were OK and he said yes. A couple of weeks later, after my new front tires were cupping, I noticed one of my front strut inserts was so loose as to be knocking back and forth.

YMMV