Why is the ‘Gutenberg’ Plugin generating an ‘Inconsistent File Permissions’ error when other Plugins, with the same permissions, do not?

If you originally installed via FTP/Cpanel/CLI the directory and files may have a different “owner” belonging to “different group” than those installed via WordPress.

One possible solution: If you have server access try deactivating Guttenberg and rename its plugin directory to something else. Then reinstall the plugin through WordPress – if this works your Dashboard plugins page will list this plugin twice – activate the one with the newest version number. If this works you can then delete renamed directory and contents.