Yeah It was losing flesh on one part of it and then randomly starting losing it in the middle, very oddMine did that recently and i am not certain why? I'm leaving mine where it is and hoping it pulls through again. I've had it for a few? years and it seems to start growing like a weed and then poof half of it fades out and disappears.
Yeah it was losing flesh so I put it on the substrate it lost more so I put it up just a little bit higher. Will check for nudibranch tonight, doubt I have any thoughCheck late at night for any culprits like montipora eating nudibranch. Hopefully not but check. Also did you by chance move it more under direct light or just lower? Looks like it's directly under LED now, was it off to the side before?