I have a pretty high flow tank, and mine RBTA keeps its tentacles fat and long, but not really a true bubble. Once its got some shrimp in its tentacles look out though cause it bubbles up like mad! I tend to agree with the hungriness.. but if that were true mine wants food the other 47 hours between feedings lol. I'm interested to see how this goes, because I haven't read anything definitive about the bubbling. There are examples of multiples in the same tank, getting the same amount of food, and some have bubble tentacles and some do not.
Mine has often showed what I would more expect from a name like bubble "tip". The tentacle will be fairly long and the very end will be blown up fatter than the rest.