Strange string in console from wpdb query

That is a placeholder escape string generated by wpdb::placeholder_escape() which is used by wpdb::add_placeholder_escape() and which is called by wpdb::prepare().

So it is safe to keep those escape strings, but there is a wpdb method for removing them: wpdb::remove_placeholder_escape():

// In your case, you'd use $this->wpdb in place of $wpdb.
$query = $wpdb->add_placeholder_escape( 'LIKE %night%' );
$query2 = $wpdb->remove_placeholder_escape( $query );
var_dump( $query, $query2 );