I wouldn’t call Bernadette incorruptible since she has a layer of wax over her face and hands to hide the effects of decay.
Bernadette was definitely incorruptible when exhumed 40 years after her death. Unfortunately, the nuns decided to bathe the body before reburial. When it was re-exhumed a decade later, the moisture was found to have discolored the face so a light coating of flesh colored wax was applied. The wax has no effect on preventing corupption, as embalming fluid would.