Continuity mistake: When Laura Knightly leans against Roy for the cameraman to take a couple photos, her face is even with Roy's. In the next shot she's above him so her chin is at Roy's eyes.
Friendface - S3-E5
Other mistake: In the beginning of the episode, Roy is explaining why Friendface is bad and chastising Jen for being on it. If you look at his monitor, he is on a website with a green color palette like the Friendface infomercial and a layout similar to MySpace. While I can't be 100% sure, it seems like a graphic designer created a mock website of Friendface to be used in the show. If true, that means Roy is already on Friendface before Jen even enters the room. (00:01:00)
Continuity mistake: The way Jen's books are stacked changes after she says "pedal stool." The book with the red pages moves to the top.
Revealing mistake: When Moss runs into the door, all walls on the set shake. (00:06:25)
Deliberate mistake: When Roy and Moss are in Jen's office talking about her slipping up, the computer monitor disappears from her table in the wide shots so you can see the actress.
Suggested correction: It's there the whole time. It's a thin monitor and it lines up with Roy's leg, so it might have been hard to see.
Fifty-Fifty - S1-E3
Factual error: It doesn't make sense that Daniel would be researching classical music, or that he chooses Jen as his 'phone a friend' because of her apparent knowledge on the subject, because there are no topic categories on 'Who Wants To Be A Millionaire' - the questions are entirely random, Daniel would have no way of knowing one of the questions he'd be asked would be about a particular topic.
Suggested correction: That's exactly why he was studying classical music, he didn't know what topics would be covered and he wanted to have a good knowledge of various topics. Since Jen appeared more knowledgeable in classical music than he did, he wanted her to be one of his phone-a-friend in case he came across a classical music question that stumped him. At the time, a contestant pre-arranged with producers 3 friends to be considered as a phone-a-friend. Daniel undoubtedly had 2 other friends or relatives that had greater knowledge on other topics than he did.
There's no way Daniel just happened to be studying classical music and seemingly nothing else, he didn't ask Jen about any other subject, the episode implied that Daniel was studying classical music as though it was a dead cert that a question would appear. This wouldn't be the case with Millionaire.
He would if he knew that classical music was an area he was particularly bad in. For example I would study as much American history as possible because it's my worst subject. But I'd also have my husband as a lifeline because he happens to be a history buff. It makes sense that Daniel would have Jen as one of his three lifelines if it seems that she's an expert at something he's awful in. Presumably his other two lifelines are knowledgeable in other strategic areas as well.