I used to work at an alignment shop, and a really amateur mistake is to do an alignment without pulling the pins out of the slip plates. That'll preload the front end while they're adjusting toe, and cause the alignment to be off even if the machine says it's good.
Take it to another NTB store, with the original paperwork, and request that an ASE mechanic do the alignment. If they just had a young tech doing it, plenty amateur mistakes could explain what you're seeing (I know, I've made most of those amateur mistakes while learning the ropes.)