On some older Covers blocks, a _doing_it_wrong is raised from rest_validate_value_from_schema, because of an invalid attribute type declared in class-covers.php. See https://github.com/greenpeace/planet4-plugin-gutenberg-blocks/blob/f7046210ab679ae0fb013c04d05ab5abfc0fcc39/classes/blocks/class-covers.php#L76

Notice: rest_validate_value_from_schema was called incorrectly. The "type" schema keyword for can only be one of the built-in types: array, object, string, number, integer, boolean, and null.

This seems to blocks the editor locally.