Practical Magic - Shifty Eyes
My friend actually pointed this slip up out to me, and when she did, I quickly went back and viewed it for myself. It's in the scene when Sally and Gary are making out, she runs to him and she wants to tell him that she's guilty and Gillian is innocent. Gary is leaning over her and the audience gets an absolute clear shot of his eyes. They are clearly blue! Then as he shifts them from left to right, looking into Sally's eyes, the left eye changes colors to be green!