Tsubasa's Resurrection - S2-E8
Factual error: At cost of stating the obvious; nobody is allowed to enter the pitch on a whim from the stands, even going as far as hitting a player kicking the football at them, it's pitch invasion. Nobody says anything about it and the referee is mysteriously absent though.
The Football Is My Best Friend - S1-E4
Audio problem: When Tsubasa says bye to his friends from the top of the overpass, his mouth is not animated for the greater part of the line. (00:04:30)
Kick-Off for the Future - S1-E3
Trivia: International versions change Roberto's message to his coach at San Paulo FC, adding for some reason that he met a girl he fell in love with. This girl is never referenced nor appears, since, well, she does not exist? Roberto mentions that he met Tsubasa instead, who he wants to bring to greatness. (00:12:40)