I had several lessons for あたらしい (新) and several for しんびん (聞), but never for しんぶん (新), until at some point the latter showed up as a "review" character that I had mastered.
There needs to be some way to ensure that all characters in the word are independently taught.
This is semi-intentional - the goal of the words is not to teach new vocabulary, but to indicate what kanji to draw.
However, I know it can be frustrating to get an answer wrong not because you forgot the kanji, but just because you didn't know the word. I have plans to improve that in the future, which should inadvertantly fix this issue as well by always showing the same prompt for a given kanji. It should be implemented somewhere around version 0.12 to 0.15
This is completed in v0.12, which will be released later this week if testing goes smoothly.
All the kanji used in a word are now shown after the kanji-prompt is complete. Furthermore, you're able to choose which word(s) to prompt for each kanji.
