Corrected entry: The first time the adult Lewis meets himself, he would have expected the kid Lewis to show up, having already experienced this meeting as a kid; this means he would not be surprised at all, but he was.
Corrected entry: After meeting the Robinsons family, Wilbur gives Lewis a pop quiz on what he's learned. Amazingly, Lewis states the relationships of the whole family, despite never having been told them or even hinted at them. For example, he states correctly that Joe is married to Billie, even though he has never even seen them together.
Corrected entry: Near the ending, Lewis gets back from the past and causes Goob to catch a baseball and win the big game. Yet, the whole movie was caused by Goob from the future, angry about having NOT caught the ball. If Goob did catch it, Lewis's memory of his adventure would be gone, but this does not happen.
Corrected entry: The whole film did not have to occur. If Wilbur was really that smart, he would have gone back in time and locked his garage before bowler hat guy stole the other time machine.