I just had this same exact problem with my BP and for me, it meant that she went into shed within the next 2 weeks so I'm inclined to believe that your BP is fine and will be going though another shed soon. One question: Is your humidity normally around 40-50%? I ask this because I had never seen my BP have this problem before till I went home for thanksgiving and when I came back she had knocked over her water bowl and the humidity in the tub was pretty much 0%. Must have been like that for a couple days. And after that, we noticed the scales. Anything like that happen to you?
In short, I wouldn't worry but I would expect a shed sooner rather than later.