Graduation Match: Part 2 - S1-E52
Plot hole: When Zane has Cyber End Dragon attack Rampart Blaster, Jaden activates De-Fusion, allowing Rampart Blaster to be sent back to his deck (and allowing Burstinatrix and Clayman to come back to the field). Later, when Jaden summons Shining Flare Wingman, he states that it will gain 300 points for each Elemental Hero in his graveyard. We are then shown eight Elemental Heroes in his graveyard, including Rampart Blaster, but this card was never sent to the graveyard, it was sent back to his deck. (00:09:13 - 00:14:43)
Plot hole: Bastion uses the special ability of Hydrogeddon, where he is able to summon another Hydrogeddon from his deck. He summons this monster by drawing the first card from the top of his deck, but there would have been no way for him to know if the card on top of his deck was a Hydrogeddon card. (00:12:35)
Plot hole: When the collection of rare cards is shown inside Crowler's jacket, the Fusion monster Ojama King can be seen as one of the rare cards. However, Chazz doesn't acquire the Ojama cards until later in the season, and he is unaware of their existence until he gets them. Also, the Ojama cards are depicted as relatively useless, unless used in the right way, so it is extremely doubtful that an Ojama card would be seen in a collection of cards that are depicted as rare and valuable. (00:08:11)
Plot hole: To escape from the students chasing after him, Damon jumps from a high ledge in the Duel Academy building and lands in the forest. Then he swings across vines at great speed, but somehow, the students all end up ahead of him in the forest, even though they were walking on foot. (00:05:30)
Plot hole: After discovering the cards tossed into the ocean at the docks, Miss Dorothy goes to Jaden's dorm to alert him of this. There was no real reason for her to go to him, seeing as how she had no idea if this incident was tied to him specifically. (00:09:05)