Possible example:
The part on (the very early episode where Homer buys Lisa a pony) where Lisa calls Homer from work, reuses footage from (the even earlier episode where Bart's dog go to disciplinary school).
Would the video the Chinese government realised said was videos of one of their piolets shooting down a plane, but was atcually cut-together from Top Gun count?
I'm baaaaaaack"Your mileage may vary, but there seems a shot taken by the actor or the producers of the A-Team at the use of stock footage in unrelated later projects when Dirk "Starbuck" Benedict, as Face-Man, startled and acted as if someone had walked over his grave when a Cylon Centurion walked by in one episode. "
Since that was used in the title sequence, does it really need to be spoilered? And I saw it more as a shout-out than a shot...
When I was a kid I was watching a lot of cartoons featuring giant mechas often formed by the assemblement of smaller machines. And one of the moments I was waiting most was the epic connection. When I grew up I realized it was just a way to use and reuse the same sequence to save money in animation. And I turned quite sad till I realized it was more than excusable. It was also a way to control the lenght of the episode by simpling cutting some seconds from the sequence if necessary.