i'll second the welding theory!!!..(if any welding took place)..i have experienced it first hand with other personal custom vehicals in past.....you would be quite amazed at the strange things it can cause to happen by subjecting the vehical to welding without proper grounding and shorting of chassis.....

i mean just take it back to him and let it be his problem to fix....it was fine when it came in! should be fine coming out, but looking twice a nice with new paint.