Continuity mistake: This is repeated with all the main characters throughout the series: whenever someone puts on their clothes, their pants underneath change colour (for example, Seiya's blue jeans turn red).
Saint Seiya (1986)
1 mistake in show generally
Kiseki no fukkatsu! Yuyo no cosmo - S1-E5
Trivia: When Seiya opens his eyes hearing Miho calling his name, behind her in the audience a particularly bored animator decided to put in some silly characters, including the Tin Man, the Lion and a girl with the look of Dorothy from the wizard of Oz. (00:19:20)