<?php
add_filter( 'content_save_pre', 'wpp_clean_google_docs' );

function wpp_clean_google_docs( $content ) {
	if ( ! ( 'transcript' == get_post_type() ) ) {
		return $content;
	}

	$search = array( '&nbsp;',
		'</span>'
	);

	$content = str_replace( $search, '', $content );

	return preg_replace( '/<span[^>]+\>/i', '', $content );
}