When the duration of a task is edited in the Task Duration column in Gantt in the save event handler e.task.taskDuration returns the new duration value. With versions, before 2020 R3, the old task duration value has been returned.
With the current version, the new task duration is returned.
The returned e.task.taskDuration should return the previous task duration in order to be consistent with the behavior before 2020 R3