On a fresh setup there are no notebooks present and afair the desktop app requires us to create a notebook first before we can create any notes. On Android with the 'Welcome' screen it is immediately possible to create a new note and save + sync it. At this point the note is not visible in the Android app anymore. Only after some time it appeared on the first notebook on the desktop and only after modifying it there, syncing it back to the phone made it visible again. I think that this 'Welcome' screen should be somewhat restricted in what we can do on it.
Just an aside, but I also don't like how the 'Welcome' screen remains the main entry point to the app. If I have it already populated with my notebooks, it should not show the 'Welcome' screen anymore.