Yes. The week in question is "Conflict" (1521-1525). Of the 305 episodes produced from 1979 to 2001, this is the only week to no longer air, nor is it available for purchase on DVD or digital download. It last aired during the week of April 1-5, 1996. No official explanation was given for why it stopped airing or why it isn't available for purchase, but it's likely due to its strong subject matter of war. In it, King Friday discovers a strange piece that Corny is making for Southwood, and soon comes to the conclusion that they're building bombs, and thus commissions that bombs be built for the Neighborhood of Make Believe, just in case. It turns out the whole thing was a grievous misunderstanding, as the pieces were going to build a bridge. It's undoubtedly the darkest story on Mister Rogers' Neighborhood, which could be the reason why it was pulled from circulation.