This happened last update also. Always use the Help menu download for now. Also there a FOUR files to download. Core, Documentation, Samples, and XBox samples.
Also remember this is not really going to update the in sim compiler, project builder, You have to wait till tomorrow Sept 7th. This is only good for the documentation and samples. The core stuff if you do wasm, and external builds with the package.exe and some 3DS Max plugin.