A bad lens, or perhaps a lens which is out of tolerance, is always possible. And yes, two in a row is also very easily possible....extremely possible. Whoever judges these lens' condition back at the shop could very well have their own itinerary.....no doubt about it.
And a lens that needs to be packed very meticulously for shipping, like a used 200 F/2 whose lens hood is mounted incorrectly in the box, thus badly scratching the barrel in shipping...yes this happens. Then you reorder and find that the next one is badly front focusing...happens very, often...yes 2 in a row!
Mike