I'm not joking as it's happened to me before. I've adjusted dates and time so that analogue hands have been apparently 'correct' but actually 12 hours out.
If your date does not change, continue using the watch and see if date changes at mid-day
Recommended procedure for setting date is to quick set (crown position 1) to the day BEFORE and then move the hands (crown positin 2) allowing the date to change over to the correct day and then set the time. Remember to move hour hand past '12' if you are doing this in the afternoon.
Do not adjust date between 20:00 and 04:00 at night, to be safe.