BUG: "Save As... " closes project
In the current version of Adobe Premiere Pro CC (Version 12.1.1 (Build 10)) if you go to "File -> Save As..." and save the project, upon completion it closes the project down, which is rather annoying.
The only work around I've found is to save the file as a different name each time I save it. I usually just give it another number or letter. Ridiculous, yes, but it works. It was suggested by Adobe. Hope this helps.