Do you notice anything in her poop? Strings, bits of toys, etc... Perhaps it is just something that isn't sitting well with her that she chewed earlier in the day and that is her way of getting it out of her system. I know those Goldens love to chew!

Dusty was doing that too for a while when he was a puppy. We determined he was allergic to the Bil-Jac liver treats we were giving him. Stopped giving them and he stopped throwing up. His was kind of happening about 5 minutes after the treats though so I don't think that is what is happening to Cookie.