Haze around exhaust pipe body work

[91C2wrencher]

I recently had a valve adj and the power steering cam shaft seal replaced. Now I'm getting a faint blue-ish haze on the body work around the exhaust pipe area. No smoke on start up or running that I can see. My wrench thinks it may be a "too rich" condition causing this haze. This is cosmetic problem for now but should I have greater concern about this?