Royal Gramma nipping at hammer coral

[Willu]

Hi,
I've had this royal gramma for about a year and as of a few days ago, I began noticing that every once in a while there would be a hammer tip floating in the water column. I was watching closely and noticed that the royal gramma was actually nipping at the tentacles. Sometimes the royal gramma would eat it. Has anyone had this happen with them, and anything I could do to help curb this behavior?

 

[40g Nano]

Feed more?
I don’t see a major problem if it isn’t picking at the skeleton, but I would let someone else respond because I’m no expert.