if (! empty( $attr['type']) && $attr['type'] == 'native') BUG

if (! empty( $attr['type']) && $attr['type'] == 'native') {
		// returning nothing will make gallery_shortcode take over
		return '';
	}

The if statement should be updated to just:

if (empty( $attr['type']) || $attr['type'] == 'rgg'){}

Because if I have some special type to do something else, your plugin breaks it. You should not assume that type is not being used by other functions or plugins…

https://www.ads-software.com/plugins/responsive-gallery-grid/