I have couple finger leathers. They slump at night but during the MH
lighting, they stand straight up and 99% of the time extend their polyps. Recently, I scraped some hair algea off my largest finger leather in my 75G. Not really thinking I used my handy tank toothbrush to scrub it off. Couple days later it was all slumped over. The area I had scrubbed looked all white and was starting to deteriorate. Couple weeks have passed and it only got worse, so, I fragged it today. I have witnessed on occassion that it would be moody..Similar to how a toadstool goes through a molt. But, this time I believe I caused it to become infected. If you have been jacking around with it, that may be the problem. If not, then check your basic water params. As long as it does not start 'bleaching' and falling apart at the base, more than likely it will get over its 'mood' and snap back. They do like iodine (Like other softies..Xenia, etc) but DO NOT over dose it. (roughly 1 cap full (5 ml) per 50G once a week or once every 2 weeks, use your best judgment..heck test even!). If it does get worse, it will pollute the tank so your best move is to frag
off the good and scrape off the bad. Hopefully, its just being a pain and you won't have to take any measures.
Keep us posted!