[shorod]

Well, it could be due to mismatched tires. One way to check that theory would be to swap the front tires left to right and right to left. If that has no effect, then do the same on the rear.

While it's in the air for swapping tires, spin the wheels and make sure you don't have a brake caliper that's hanging up.

I would expect that the person doing the alignment would have noticed if there were any loose steering or suspension parts, unless they noticed the bad tire before even getting it on the alignment rack.

-Rod