Dark matter black holes will lag behind galaxies in motion because they are only dependent of the local Higgs field (Casimir) pressure without graviton pressure on their nuclei.
According to Quantum FFF Theory: BHs have no singularity at the center, but a complex concentration of dark matter Qauntum knots instead, also called Axions or Weyl fermions and even Higgs particles. see also:
http://www.dailygalaxy.com/my_weblog/2015/12/dark-matter-debate-a-totally-new-exotic-form-of-matter-todays-most-popular.html
https://www.flickr.com/photos/93308747@N05/collections/72157652122028862/
