On their 25th wedding anniversary, a couple makes a big celebration, and displays their framed ketubah in the party hall. Someone notices the date on the ketubah and remarks to the couple, "The date on the ketubah is wrong. Yes, you were in the catering hall on Sunday afternoon, but since the chuppah occurred after sunset, the date should have been changed to Monday, a day later."
Do they need to change the ketubah? Are there any other halachic problems with their marital status retroactively having co-habited with an invalid ketubah all these years?
Related question - What if only part of the date was wrong. Let's say correct Hebrew date but wrong day of week or vice versa?