Stylophora/birdsnest question

[Psiber_Syn]

Starting to see some white show up on my nest i have a few crabs red legs, hermits, emerald crab that all seem to stay in the nest are they eating it cause the white is just in spots i just have moved into a bigger tank but its been a week or so under new vho it was under t5 and leds could this be caused by the stress i lost the hugs nest colony that these sit in to rtn hope this dont happen again

 

[Tommy's Reef]

It looks like it has a whitey fleshy eating a way diease of sum sort

 

[Psiber_Syn]

Its on a few parts but not on other pieces in the same group