Well, usually they only soak if they're going into shed, or if they have mites. If it's neither one of those, it could be she just felt like soaking. Sometimes it can also be that they're trying to cool down, but from the temps you provided I wouldn't say that's the case either. My feeding day was yesterday, and a couple hours after I fed my bloodred corn he was soaking in his dish as well, and he had just shed the night before. Maybe sometimes they like to bathe after eating? haha I wouldn't worry too much, doesn't sound like anything too weird.
Couldn't have said it better myself. She just may just have felt like soaking. I wouldn't worry unless you see happening consistently.
"We are artists using locus and alleles as our paint; the ball python as our canvas" - Colin Weaver