John (Harcourt) de Harcourt (1272 - 1330)

The marriage date is before John's birth date, which is of course impossible. If the marriage date of John and Matilda was later that would be even later after their daughter Alice's birth - and also longer after Matilda's death. If Alice's birth was later, perhaps abt 1295, it would still work with Alice's son Henry's birth of 1315 and would follow the more common practice of the time for the wife to be younger than the husband (rather than 19 years older than John De Musters as is shown now). Matilda's death also being 1295 (to keep with her death being the same year as Alice's birth, or at least not before Alice is born) works but it does mean she would have been 60 when she gave birth. That's not common now and would be even rarer in this time period. John and Matilda's marriage date of 1294, one year before Alice is born, fits with Alice being the first born and John would be 22, which is well within the normal range.

However, the most parsimonious explanation is that John's birth date is wrong, and that he was born around the same time as Matilda.