Strange one, got 63 plate boxster serviced before Christmas checked oil level one bar below max ran fine no issues then in new year warning popped up oil over fill and when level checked oil at max how does that happen? Do I drain some out or is there something else it could be?
The oil level sender can give the odd wonky reading. I once had a low oil warning and when I cheked it after restarting the car the level was fine. I would not get too worried by one spurious reading.