Hammer coral melting - thoughts?

[604reefer]

So I have 7 different hammers (yeah i know...) and one of them is just melting away.

There's no BJD or any evidence of pests. I've tried moving it to no avail, it's been slowly melting for a month. At first I thought it was maybe splitting as all of the large hammer tips split into smaller ones, then I noticed parts of it losing color, but the color came back rather quick, yet it's still receding. In the past week it's really picked up speed and is almost gone.

About 2 weeks ago I dipped it in revive, it slimed, then perked up a bit, then continued to decline. Today the mouth was VERY WIDE open and tissue receding to almost the point of the mouth. Tips are almost completely deflated and limp.

It's so strange, everything else around it is thriving, splitting, growing, etc. Tank params are all within ideal ranges, no changes to lighting or what I use in the tank.

Any thoughts?