Called on a job a few years ago with a "hot call" ac complaint.
Home warranty company had replaced the horiz. gas furnace, in the attic, a day before Thanksdgiving. Found the furnace was sucking attic air because the RA plenum was shy by 6" to being attached to the furnace.
Closer look, I realized that the furnace was setting on bricks and the furnace outlet was "aimed" 6" to the supply outlet. No attempt was made to hook-up either plenum.
The installers probably made it to the liquor store in plenty of time before it closed.
Home owner got his money's worth with the $35 deductable.