Day & Date on Aquatimer Chronograph out of Sync.

Hi,
I might seem a little daft but having received an IWC Aquatimer Chronograph for my birthday, I have noticed that the Day and Date change at different times. The day is changing over midday, and the date at midnight.
Wouldn’t have thought that possible but somehow I have managed to confuse the watch! Anyone experienced this before, perhaps I need to visit an expert to have the watch services and realign the movements?
Any experiences, advice much appreciated.
Rob.

Thanks Tonny. Will go get the service sorted out.