Wall hammer flesh receding/disappearing

[thisguy1]

So for the past for weeks I’ve noticed my wall hammer flesh has been disappearing or receding. Last month I noticed little patches/holes that’s revealed the skeleton but I actually forgot about it until recently I looked and a lot more has disappeared. But even tho is happening my coral is doing completely fine. It’s puffy and eats just normal. Also noticed tho the flesh is disappearing around the edge of the coral the flesh inside or behind the edge still extends. I’ve taken pics it’s the best I can get right now kinda hard to see. But if anyone has ideas about what’s going on I’d greatly appreciate it.

 

[PokeFish]

That area where its receding is really close to sand. Maybe thats the reason.