Skin type is not only judged by the color it seems. There is underlying pigment involved when people have certain ethnicities mixed in.
Does she use compression during treatments? Gliding? Both? Neither? Did she press down on some of these areas and not others?
Using correct method in applying the machine (i.e. not just settings set) is very important on this particular machine which is hard to use. Pressing down is important, especially when using gliding (not recommended).
Did you show this to the clinic yet and got their response? Do you have an idea whether they think the machine is malfunctioning?