gutenberg problem

I assume you’ve already done this, but in case you haven’t, update your Gutenberg plugin to the latest version. As it’s still very much in Beta, many bugs and features are still being ironed out, but these issues you encountered should have been fixed in updated releases of the plugin. If you still have the issue, deactivate all your plugins and switch to a default theme (like twentyseventeen) to see if it’s a conflict with a theme or plugin.