If all of your husbandry is spot on there is no "reason" for your snake to soak. That being said, some ball pythons will soak quite often and some never will.

If your snake doesn't have mites, has appropriate tight fitting hides, and the enclosure has 60% humidity normall and 70% during shed, then your snake probably just likes the occational dip.

Rule out mites, improper humidity, and inadequate hides before assuming your snake is fine.