I think if they really delay it, they should announce it official and dont make a twitter post and delete the post after some minutes. But i dont think this will come out this year, they have announced gameplay 2 times and we have still only cinematic trailers. So i dont think what i should think about a 2017 or 2018 announcement.
I think the sinking city (another Call of Cthulhu game) will come out earlier, it is announced for 2018 and from the sinking city we already have gameplay...
Has anyone heard any updates on the release? Last I heard was Summer 2018, but with summer approaching and silence around, i feel its an unlikely timeframe.
The team at Cyanide is still working on the game. We should have more info about Call of Cthulhu at E3.