I have personally witnessed JoAnne employees take a black non Kona broadcloth bolt end of approximately 5 yards of fabric and put it on the black Kaufman Kona bolt. That was the last time I bought quilting fabric from JoAnnes. They were not doing it to be deceitful or rip off the customers they just don't know the difference. The problem is most of JoAnne employees are not sewers, let alone quilters. To them one black solid is no different from another. This would explain why the OP and many others who have posted the same here felt the fabric is different weight/quality from Kaufman Kona.
Anytime I have order Kaufman Kona solids on line from Fabric Depot or Hancocks of Paducah, I have always gotten the Kaufman Kona that I expect. Same goes for Moda Bella solids from Thousands of Bolts.
I have not tried Hobby Lobby because it is less expensive for me to order from Hancocks of Paducah on line even with shipping. And it is much more convenient for me to shop the net.