Continuity mistake: When Dumbledore reveals the scar Wormtail made on Harry's arm, the blood around the scar differs in the next shot.
Continuity mistake: When Moody has turned Draco into a ferret, McGonagall shows up asking what he is doing. Behind her Harry is holding onto his bag's strap. His hand's position on the strap changes in the next shot.
Continuity mistake: When Voldemort says to Harry, "I'd introduce you, but rumor has it you're almost as famous as me these days," we see Harry resting his chin on the statue's sickle. When it cuts, he has his chin lifted from it.
Continuity mistake: During the scene in which the Tri Wizard cup is brought into the Great Hall and then Harry's name comes out of the Goblet of Fire, pay attention to Hagrid. We first see him move behind Snape and Moody who are in front of the window and standing directly behind them. Then he is further over to the right of the screen in front of the wall, and then back to his original position.
Continuity mistake: When Voldemort pushes Cedric's face with his foot, his foot's placement on Cedric's face change in the next shot.
Continuity mistake: When Harry falls into the Pensieve and sees Dumbledore, he leans towards him. In the next shot, he is noticeably further away.
Continuity mistake: When Harry returns with Cedric's body he says "He's back. Voldemort is back". When it cuts Dumbledore suddenly has got his hand behind Harry's head. It wasn't there in the previous shot.
Continuity mistake: When Harry wakes up after having his first nightmare the pillow under his head change position in the next shot.
Continuity mistake: When Harry returns from the cemetery, there's a shot of him lying over Cedric's body. When Dumbledore reaches out to put his hands on Harry's face, Harry's left shoulder is higher while he rests his weight on his right arm. The scene cuts to a rear view, and his right shoulder is now higher. When it cuts back to a front view, his left shoulder is once again in the higher position.
Continuity mistake: In the scene where Hermione makes Harry stand up after his name has been retrieved from the Goblet of Fire, Ron continues to look straight ahead and has an emotionless expression for that shot. In the next shot when Harry is walking to Dumbledore, Ron's head is suddenly slightly down and moving up towards Harry, and a glare has appeared on his face.
Continuity mistake: When Dumbledore rages on Harry and asks him if he put his name in the Goblet of Fire, he first only put his right hand on Harry's shoulder, but in the next shot his left hand also appears on the other shoulder.
Continuity mistake: During the first challenge, the arena/stadium is significantly smaller during the bird's eye view CGI scenes than the physical scene's interior shots.
Answer: Not at all. In fact, David Heyman made the decision for his eyes to be blue in the films for him to be more scary! They felt that his red eyes in Sorcerer's Stone did not show enough emotion to make him an evil character. It was felt in Goblet of Fire that the light blue eyes would be perfect to show his evil in the moonlight, and they kept it on for later films.