Any pics of this shed?
It's not a good idea to soak BP's before they shed. Soaking is more a corrective action when a shed is bad to get the remaining pieces. Just one bad shed will do no harm to your BP. Just keep the humidity over 50% and the next shed should be one single piece.
Also something that may help, when you notice your BP going blue put some moist Sphagnum moss in their hide to keep the humidity nice and high in there.