Character mistake: Lorraine mistakenly tells Denny to "call 999" instead of 911, and when asked about it by Katie, denies having ever spent time in the UK (later revealed to be a lie). But this isn't some high-pressure slip of the tongue, she's highly intelligent and has been in America for a decent length of time, is working hard to maintain her facade of being born and bred American, so there's no way she'd slip up over such an obvious thing.
Boston Legal (2004)
1 mistake in season 4 - chronological order
Starring: James Spader, William Shatner, Candice Bergen, Rene Auberjonois
Alan Shore: Ah, Denny, I've hardly seen you this episode.
Trivia: Alan mentions networks even censoring their scripted shows - that's a pointed reference to the fact that ABC executives ordered any explicit references of Fox News to be removed from this episode.