I honestly believe it's a curse to put "coming soon" on any project. I learned that a long time ago. I also see a whole lot of artist come in & get major props by simply stating they're about to start working together and drop an album. Yet, them projects themselves never see light of day as well.
I try my best to make sure to let it be known it's an idea if I'm asked about a project, or state how much of it is done, but still make it clear that it may not come out due to not being completed.
Everything else, I set a date, or add "coming soon," but that project is in fact done by the time I do that.