Continuity mistake: Mike and Kara are in the alien bar in the both talking about Mike not controlling his powers. When Mike breaks the glass there is no other glass on the table. In the next shot a glass appears at the edge of the table, in the next shot the glass is gone again. (00:03:30)
Supergirl (2015)
1 mistake in Changing - chronological order
Starring: Calista Flockhart, Melissa Benoist, Mehcad Brooks, David Harewood
Cat Grant: All four of you standing there doing nothing, you look like the attractive yet non-threatening, racially diverse cast of a CW show.
More trivia for Supergirl
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.