掲示板 Forums - Words that cannot be reviewed

For the past few days I have the following problem. At the start of each day, beginner words for Japanese will have some words (e.g. 13) that can be reviewed. When I go to review these words, the quiz will only have some questions (e.g. 10 out of 13). The remaining questions (e.g. 13-10 = 3) then cannot be reviewed. When I click on the study button, I just get stuck on the loading page. Here’s a photo for reference.