Briefly describe (1-2 sentences) the Bug you’re experiencing**: Some of my non-reoccuring tasks that were completed a month ago keep popping back up as incomplete. I currently have 52 flagged incomplete tasks from April that will not go away, even if I mark them complete again or try to delete the task altogether. I am using the free version. This is happening in both the Web & App versions.
All of those tasks shown in your screenshot are subtasks (note the “<” showing the subtask on the left and its parent on the right).
Perhaps the subtasks are not recurring tasks but the parent is? If so, then the subtasks get recreated along with a new parent when you mark the parent complete.
Unpredictable things happen if you have have recurring subtasks in recurring parent tasks, so you must avoid that.
You can also check the audit trail of stories in the parent and subtasks. That’s the fine print in the task detail pane you see mixed in with the comment thread showing the history of what happened to the task/subtask. That can provide clues or confirmation.