Hi there,
the Gutenberg plugin is under constant development, its effectively always in Beta ( or more likely alpha ). Its there for developers to test experimental features that may make it into WordPress core in the future. As it is experimental it comes with lots of bugs. And we therefore recommend that no one uses it on a live site, as it will break more things then it improves.
As a note: All of our future proof testing is performed on Beta versions of WordPress not using that plugin.