What a bummer... send "the boss" back undeneath and have him look for two things.
1. Any bulgeing of the axel between the two U bolts.
2. Any tilting of the wheel. You can use a level on the tire.
That is hold the level verticle and view the small glass at the end. It's hard to see but if the castor/camber is out it should be different then the other wheels. Remembe a tire with load on it bulges at the bottom. You nee to put the level on the rim, or use a wooden block on the rim to stand the level off a few inches if it's to long.
Let us know how you make out.