This is a piece of cake job. Everything is intuitively obvious.

You said you saw the leak on Christmas. What was the temperature when you saw it? If it was freezing or colder and it is not leaking now, don't worry about it. This is a cold weather leak because the shaft is slightly contracting. Unless you stay in weather this cold much of the year, just live with it, it will leak very infrequently.

Good luck,