I’ve got that on my current plan as I shifted everything back a week due to a getting a cold back in October. So I think it’s the Plan Builder code and the code behind the push/pull functionality not being integrated in how the latter modifies a plan. Might be wrong on that but it seems the most likely as some of the individual phase/plan descriptions seem a week out. There was also a popup at the time stating that making the change would mean I wouldn’t be able to update it in future.