Maybe try a humidity hide: https://www.youtube.com/watch?v=tjBFKkbJrRE&t=1s
As long as your BP doesn't spend all day inside the humidity hide, it can be good to keep one in the enclosure at all times especially if it's a light coloured snake which makes it hard to tell when it's going into shed. If humidity isn't bumped up early enough in the shedding process the shed could end up being bad.

Bad sheds can also be caused by illnesses, malnutrition, and parasites but there are usually other signs of these problems if they are present.

Could it be that your hygrometer is inaccurate?