Not unusual especially in the summer. My wife and son were flying there four years ago when this happened. Their connecting flight was held in Baltimore for over five hours. When they were finally airborne, storms popped up again and they were diverted to Ft. Myers. Were then supposed to fly to Orlando but the flight crew reached their maximum flight time. Screw that, while at home in CT, I rented them a car and they drove the rest of the way. They checked into the Beach Club and since it was extra magic hours at the MK, they hightailed over there. A 1:00 planned arrival turned into a midnight walk down Main Street. At least they have a story to tell.
PS: Tracking their flight online, it landed in Orlando at 11:45pm so they made it to the park before they would have boarded their Magical Express bus.