IMO it is a common result of damage or injury. Anemones can develop growths like this during the healing process. My opinion is that it is just that. I could be wrong, but I've never heard of a Haddoni reproducing by budding. At least not successfully. "Baby anemones" have been witnessed growing or forming on occassion, but I have never seen a resulting separation where you end up with two healthy anemones. As Minh has mentioned, others have tried to remove them, but they do not survive on their own.