Bizarre unknown birds nest and pocillopora disease

[Bongo Shrimp]

My gf works at a lfs and they have been having a weird problem with their birds nest and pocilloporas where the tissue will recede leaving the gray skeleton behind and when you cut it the insides of the branches are hollow and filled with black slimy stuff.

Anyone seen this before or know what it is?

 

[Acronic]

Aftermath of the oil spill? Depending where these corals came from of course