I saw this on my reputation changes for September 14, 2015:
so I checked the three questions where I should have unaccepted answers. Since after a whole day the situation didn't change and the reputation page still shows wrong data, I thought it better to ask here.
Yes, I still have the green tick; when I saw the three “unaccept” marks, I went to see and found the ticks were still there:
Note that this is the complete report for the day and no “voting corrected” or “user removed” entry is shown, so this apparently is not something due to serial or anyway bad voting. If it is, then we have a different bug. In other words: if the “unaccept” is not a voluntary act by the user, I should be notified that this “unaccept” is a correction by the system.
In Normal Human's answer below, the picture shows “voting corrected” entries, which makes his/her case different from mine.