Would you believe something similar happened to me. 5 days before we were to fly out, as I went to check in online I noticed my youngest childs passport was out of date. In Ireland if they are issued under the age of 3 then it lasts for 3 years and 5 years for under 16 and 10 years for an adult.

The difference for me was that it did make a difference and I had to get an emergency apt with the passport office. Only got the passport 4 hours before our flight....