Patrick, are you saying that the successor task is not properly be set to start after the predecessor task? This is my assumption, but I want to make sure it isn’t the line that’s the problem. Anyway, hard to detect. You might try using the task inspector (Inspect task under the Task ribbon). Are they auto scheduled tasks? If they are manually scheduled tasks then they won’t move automatically (select Respect Links under the Task ribbon). Let me know if either of those might help.