This was an issue during the beta and also after the recent dictionary updates, but it seems to be still happening. I currently have 1 term to study today on vocab schedule 15483, and despite completing the schedule with listening questions allowed and flushing the schedule, it won't go away. I also had a similar issue with some of my kanji schedules a week or two ago, but I was able to remove the extra terms by flushing the schedules.
Alright, I'm keeping an eye on it so let me know the next time it pops up, and I should be able to jump in and check it out! The easiest to fix will be any schedule that has the issue and cannot be resolved by the flushing method.
I finished studying vocab schedules 15483 and 15489 for the day, then flushed them, but they both still list one term available to study. Of all the schedules I regularly study, these two have consistently had this issue for the past 5 days.
I haven't been having any problems with the vocabulary schedules, however, some of my kanji schedules still occasionally show terms to study hours after I already finished the schedule. The differences from the vocab issue are that the terms in the kanji schedules are flushable, and the extra terms don't appear immediately after finishing the schedules. Today, for example, I completely studied my kanji schedules 14170 and 33313 in the morning, and both the schedule pages and the dashboard showed both schedules as completely studied. Then, this afternoon when I checked my dashboard after studying my vocab schedules, those two kanji schedules were listed as having terms available to study (2 level 9 terms and 1 level 3 term, respectively). This bug only seems to happen once every few weeks, but it's been consistently happening for a couple months now.
