Okay, here's the deal: Chinese television guidelines are yucky.
The YouTube episodes (from the official source) all SAY they are about 21 minutes, but that's very much not true. When you get into the teens, there are some fun jump cuts and missing scenes. This is a danger until the end of the series. I'm not entirely sure what was cut out, but I can assume it was scenes that would imply too much / wouldn't get past guidelines (portrayal of homosexuality in Chinese media, is—essentially, banned).
The way around this? Turn on adblocker and jump over to KissAsian, DramaCool, or any other snakey uploading site that steals translations to watch the full episodes. I watched all 30 full 21 minute episodes on KissAsian just fine!!
I hope this is helpful and saves someone confusion. Happy watching, kiddos!
Full link: https://kissasian.video/drama/advance-bravely.html