Did anything else even remotely have an opportunity to happen around the tank?
It looks almost like a chemical poisoning to me... maybe somebody dusted the room that the tank is in and some very fine Pledge dust got in there, or painting/refinishing anything else in the house.
I've also seen turbinaria that get the whitish color on them like that when there is a relatively rapid change in salinity or temperature... it looks stressed.
As for the polyps, that almost looks like some kind of black cyano... hard to tell in the pic so I'm not even sure if I'm looking at the correct thing in the photo.
No other changes, maintenance (water changes, etc.) happened within 1-3 days before?
Oh, and the last pic looks like some type of encrusting pavona species. Do some digging and searching on the many varieties of pavona... they are an SPS coral and very frequently come in as hitch-hikers on live rock... they may go undetected (almost kind of dormant) for months after you get a new piece of live rock, then one day "BOOM" there it is!