This has been going on for years. If it says I have 5 terms to study, I actually have 6. Kanji and Vocabulary counts are accurate, but Grammar counts are always one off. Am I the only person to have this problem?
Sorry about that! It is possible that the issue existed before, was brought up and fixed, and reappeared.
However, I'm unable to know of an issue if it isn't brought up. It looks like the schedules have all been fully studied at the moment, but if you let me know the next time it shows that data (and not study it afterwards), I'll be more than happy to check it out!