Nope, I haven't myself known anyone to do that. At least, not in the extreme.
This may not be a total "walkaway" situation in terms of assuming a whole new identity, etc., though.
ML is young.
She may just be making some decisions about what path in life she really wants to take.
So, it may not be a case of ML "walking away," so much as "choosing to walk a different path."
It may also just be something she impulsively chose to do, because of emotional stressors or other pressures she was experiencing.
Again, IF she is voluntarily missing at this point.
That's a big IF.
JMO.