I have a list of tasks that I do on a monthly and quarterly basis. When the tasks are completed, I go tot he task and mark it as complete. This has been working well for me for several years until last month. Now, when I mark the current task as complete it temporarily is marked as complete, then after a time it or a restart of the program, it is marked as incomplete. I have deleted all tasks and manually put them back in. I have tried closing all add-ons and reopening Thunderbird in safe mode. None of the tasks are marked "read only", so that isn't the issue. I have searched the forums but could not find anything that truly addresses this issue. Sure, I can turn off the reminders checkbox, but that defeats the purpose of having a task reminder. How do I fix this issue?