upgrade 7.6 broke my code: “head> style [amp-boilerplate]”

On the update the plugin , again my AMP pages was broken , the message that appeared it is:

Notice: Uninitialized string offset: 0 in /home/escolaedti/public_html/wp-content/plugins/wordpress-seo/frontend/class-twitter.php on line 495

A tag “head > style[amp-boilerplate]” está ausente ou incorreta, mas é exigida pela “noscript > style[amp-boilerplate]”.

translation:

A “head> style [amp-boilerplate]” tag is missing or incorrect, but is required by “noscript> style [amp-boilerplate]”.

So how can i fix this?

follow to the path
/wp-content/plugins/wordpress-seo/frontend/class-twitter.php

and change the function to:

/**
	 * Outputs a Twitter image tag for a given image
	 *
	 * @param string $img The source URL to the image.
	 * @param string $tag The tag to output, defaults to image:src but can be altered for use in galleries.
	 *
	 * @return bool
	 */
	//protected function image_output( $img, $tag = 'image:src' ) {
	protected function image_output( $img, $tag = 'image' ) {
		/**
		 * Filter: 'wpseo_twitter_image' - Allow changing the Twitter Card image
		 *
		 * @api string $img Image URL string
		 */
		$img = apply_filters( 'wpseo_twitter_image', $img );

		$escaped_img = esc_url( $img );

		if ( in_array( $escaped_img, $this->shown_images ) ) {
			return false;
		}

		if ( is_string( $escaped_img ) && $escaped_img !== '' ) {
			$this->output_metatag( $tag, $escaped_img, true );
			array_push( $this->shown_images, $escaped_img );

			return true;
		}

		return false;
	}

Now it’s fixed!

Why the developers doesn’t fixed that yet?!?!