Continuity mistake: When J'onn J'onzz is fighting Miss Martian in the ring, she punches him into a wall, leaving a massive dent. She missed the next punch, and the plaster on the right hand side of the dent falls out, but the plaster on the left is fine. Miss Martian then throws J'onn across the room, and in the background, the dent is visible, but it is now the left hand side of the dent where the plastering is missing and the plastering on the right is now mostly in place.
Supergirl (2015)
1 mistake in Survivors
Starring: Calista Flockhart, Melissa Benoist, Mehcad Brooks, David Harewood
More quotes from Supergirl
Trivia: The episode "Exodus" introduces Mon-El's father Lar Gand. In DC comics, Lar Gand was the birth name of Mon-El.
Question: Why did they change her costume and hair style?
Answer: I can't say for certain, so I'm surmising that the change was to "catch up" with the other Arrowverse shows, particularly Arrow and The Flash, whose lead characters have undergone various upgrades and redesigns of their superhero suits over the years; after four seasons, Kara's probably just felt a little stale. And I believe the change in hairstyle was Melissa Benoist's personal decision and had nothing to do with the character.
Answer: Another part of why the change was that it's cold in Canada in the winter and the old costume didn't protect her from it, whereas the new one is nice and warm.