Regardless of how late it is, you need to treat today more like day 28 or even 27 for the egg because it will take just as long for the baby to get ready to hatch as it would if it were on time; perhaps even longer. Sounds to me like there wasn't enough moisture loss in your other egg. Hygrometers, in my experience, are rather inaccurate tools unless properly calibrated and tested. 55%, for all you know, could be 75%. I've had hygrometers that were 30% off or more. It is very dangerous with eggs. People suggest high humidity for geese but in my experience... Geese are usually hard to hatch because people keep their relative humidity too high, which does not occur in nature. Just my thoughts. I hope your gosling makes it. Remember, patience.