I have never seen Majano in person, but I just checked out some photos online and I don't think this matches. Perhaps not fully matured yet. It does have two rows of tentacles like the zoas (one up and one down) and is similarly sized. The tentacles don't look like the ones I saw in pictures of Majano. However, the center looks different than my zoas. Yes, the bubbles are the grape caulerpa.
I do have a few green bubble algae bubbles and am more determined than ever to get rid of them. I recently acquired all of the liverock, and sand from a 72 gallon tank that was completely overrun with Aiptasia and Bubble Algae. There was not a 4" sqare space anywhere in that tank where there was no Aiptasia. Some of those bubbles were the size of large cherries and I saw Aiptasia heads that were 2-3 inches in diameter! I was going to clean one rock at a time, so I brought them home and put them all in a plastic bin full of saltwater with a heater, but no circulation. It never occurred to me that Aiptasia needs oxygen to survive, so, in less than 48 hours all of it was dead. There was a scum on the water and the smell was like low tide, multiplied by ten! It was so nasty, it burned my eyes when I entered the room. I spent much of Friday blasting those rocks with fresh water from a spray nozzle in my driveway. I sprayed off all of those slimy Aiptasia polyps and Bubble Algae. The Aiptasia looked like rotting oysters and smelled as bad. Now those rocks are on my roof, waiting for some sunny days to completely dry them out before I re-introduce them to some other liverock. I expected my driveway to smell awful today, but apparently, the rain washed away all of the stench. I also found a 7" and a 9" bristleworm (dead, of course) while spraying off the rocks.