Tomas, interesting issue. It could be some sort of corruption in the task but let me ask some questions for you to try. 1. Add the Actual Start column and see if there is a date. If so, remove it 2. Is any of the tasks manually scheduled. If so, change them to auto-scheduled 3. When you are recreating the task/project, are you selecting the entire task? If so, you are copying everything about that task, not just the columns you see. Try creating a new task from scratch and then deleting the original task.
Good luck, and let me know if any of the above finds an answer. Thanks…Larry