It's confusing, I think, because of the Kona Bay brand of fabrics. Kona Bay is a different manufacturer than Kaufman.
From what I have read elsewhere, I think that fabrics simply labeled Kona or Kona Bay cannot be assumed to be Kaufman Kona fabrics. For me, I just always look for Kaufman on the bolt or in the description. I seldom shop for solid colors, so have not run across the non-Kaufman Kona so far.