Yep. The way I heard it explained is that they are not sure that the stuff that makes up the singularity at the center of a black hole is even matter anymore...
Wha??? Then what in the world is it???
A black hole is a very simple object: it has only three properties mass, spin and electrical charge.
I guess when you take the neutrons of a massive neutron star and smash them together until none of the nuclear forces can maintain the structure of the quarks or whatever sub atomic particles are there, then it is beyond our imagination and way beyond our ability to reproduce in a lab.
God's creation is amazing!