We're told she's upset because people think she was insulting Kris Jenner, who was presumably behind the quinoa, gourmet crackers, I Can't Believe It's Not Butter ... and other healthy items purchased. Remember, he's diabetic.
Sources close to Rob and Chyna tell us they have a strict no carb rule which has been instrumental in helping Rob shed lbs. We're told Chyna was just busting on the carb-filled selections in the cabinet -- and has zero beef with Rob's mom.
Besides, we're told Chyna doesn't even buy that Kris picked out the food. As one source put it, "When's the last time you saw Kris Jenner inside a grocery store?"