On the tab Project/Time Spent there is a list of consumed time, spent on the tasks of the project. Each line is showing a pencil icon to allow a modification of the data.
In edit mode, the assigned task can get changed to a different task of the project. Upon saving the edits, this change is getting ignored, the old task is still assigned:
We need to update the fk_element referencing the task, but we also need to adjust the values for duration_effective of both affected tasks (old and new).