The "slip-up" I found is in the creaming room. ( I don't know what it's really called). But, when they walk in, you see all of the little oompa-loompas working and doing their jobs.

Well..there is one oompa-loompa who is supposedly measuring the amount of smoke that is coming out of the machine but in actuality, you see him pumping a pedal with his little leg. I thought it was kinda funny...because when the pedals run out of smoke, you hear a big hollow kinda thump.