In the episode "Hal Grieves" go to the scene when Dewey and Reese are in the kitchen and they are starting to take advantage of Hal. Just after Reese says, "I guess the problem with memories is they fade..." Pay attention, the next line he says doesn't match up with the clip. It's a short clip, but there's a tiny pause where his mouth isn't even moving and it looks like he was supposed to say "I know" or something like that.