Has the soaking only been since after the PAM treatment? I ask because even a slight exposure to such chemicals may instinctively need 'flushing' from their body, which is what the soaking (hydration) might be about? Just a guess, if you're SURE there's no mites, & that the temperatures aren't too high (what is the cool side reading in her enclosure???) & that your temp. readings are accurate. Some snakes soak for moisture, others for the cooler temperature relief, & others to try to get rid of mites. It's up to us to "play detective".