Shedender or Deshedder

Hello I am new to the forum. My one cat is a male all black- I think he is part maine coon. Very Big with a course top layer and a fluffy under coat.

I was brushing along with the deshedder and it was working REALLY good and then I looked and noticed - It removed ALL of his undercoat!!!

There is nothing but his top coat...anyone else have this experience?

Nope, can't say I have had that experience.