Sometimes flushing works, sometimes it doesn't. I finished my last quiz of my kanji schedule #14170 and was shown the study new terms button at the end of the quiz; clicking it gave the message "Congratulations! You have sufficiently studied this personal schedule, so you have no terms that are ready for review. Please try again in a couple days!". I tried to submit a bug report from the quiz page, but I got an error message -_-; In this case, flushing the schedule fixed the problem, but this seems to be happening now on a fairly regular basis, at least once a week, when before the last month or so I hadn't seen this kind of bug in months/years, so I thought I'd mention it. Not sure if the problem is specific to the beta or not, but something seems to have changed recently to be causing this issue to be reoccuring so frequently again.
It's about to reset, so you probably won't see it in time, but it happened again in my schedule 15489, complete with the error when I tried an in quiz report. A pattern I've noticed that might be related: this bug seems to happen when I finish a schedule later in the day, especially if I did part of it early in the day and came back to it later. Also, oddly, this time the schedule is listed as complete for the day on the dashboard, but the schedule page still shows the new terms to study button.