In the part where new terms are introduced, selecting a different option under the "I know this term" section changes the current word to a different word in the web version of renshuu. However, in the mobile app, making a selection not only does not change the current word, it also changes the choice for the "I know this term" section of the rest of the new words to whatever option you selected last. Tested on a Huawei P30 running Android Pie (9)
Oh...the word's not changing? That must be the error, not the color of the link. Thanks - I'll let you know when I have it squashed! Do you mind letting me know which list or schedule this is for?
Oh! Ok - so the text on that page is wrong. With a list, there are no terms to replace them, so this is just a marker to help you mark up your levels. I'll fix that text.
Additionally, I added some responses to make it clearer what is happening! Hope this helps.