"Say it again."
I was thinking the same thing! In my Chinese class, my teacher (who lived in Taiwan for over 40 years and is a native speaker) had always included "请" to indicate that it was a command. I was disappointed when it counted my answer wrong, when in reality it is correct. I filed a bug report for it.
Ok, where's the consistency. The first few times this was presented to me, the Chinese was "你再说一次“， now it's counting it wrong, and saying it's "再说一次”。 Pick something, or if you changed it, explain that, don't just change it, then suddenly mark something wrong that was right before, and something right that was wrong before. Sure fix it, but when you have made changes, document them in the answers given. I really am trying to learn, but also fighting the frustration of a system that obviously has limitations based on the fact that the system is still being built. It would help lessen the frustration that when an answer is updated, that it has some sort of notation that pops up that explains the reason. (i.e. better accuracy, better grammar.) Also with the "sentences" indicate if the situation is spoken or written, as answer A works better in spoken situations, while answer B works better in written ones.