Revealing mistake: Oliver Babish's office has windows in a location it can not possibly have them. Jed and Leo are in continuous conversation as they leave the 'normal' West Wing set at the end of a hall (See http://www.whitehousemuseum.org/special/wwtv.htm where the words 'Press Briefing Room' are - that's where they turn to their right). They walk a few steps then turn right again and ahead of them is Babish's office, with windows straight ahead. If this had been a single continuous set, Babish's office would be located in the stair area to the left of the press briefing room, and the windows would offer a view of the hallway that runs between the lower corners of Leo and C.J.'s offices (seen at 3:36), not the outside world. (00:03:30)
In the Shadow of Two Gunmen: Part I - S2-E1
Revealing mistake: When the Secret Service drags Hoynes out of the White House lobby, they exit through the main entrance, doors that are shown in episodes before and after as leading directly outside. But instead of seeing a convincing night exterior this time, the flashing cameras reveal nothing but a blue studio backdrop is out there. (00:06:30)
Chosen answer: A really annoying innate lack of sense. My friends and family say the same thing all the time, and I'm endlessly trying to correct them. I think people just don't know any better and (ironically) couldn't care less that they're speaking incorrectly.