one environment to another. This is not a 100% thing, but it is common. You may have perfect husbandry, and still get a bad shed on a new snake. I had a rescue not to long ago, and after it turned blue, I ran its tank with several hides around 75%, it had an awful shed. Its next shed was great at the same humidity. If your husbandry is good, your next shed will be better. 50% to 60% should be good for a ball python normally, but a humid hide will give the snake a chance to get more moisture before a shed. I usually put a wet sponge in a 1 1/2 inch pvc pipe to make a humid hide. Wet the sponge when the belly gets pink or the eyes get blue.
Don't worry to much about a first bad shed.
David