If it is leaking around the circumference of the wheel / tire, I would suspect:
1) some build up around the bead seat of the wheel. ( they didn't scrub the wheel with the little dish scrubber thingy my wife hates that I use then put back...)
2) they had trouble mounting the tire, ( not warm, didn't use lube...) and just used gorilla force and long leverage on the tire, and mucked up the bead on the tire......
3) or both.
kjf