Solution:
Click Avada -> Theme Options -> [Save Changes]
to reset the Avada theme cache.
(Click [Reset Fusion Caches] under Theme Options -> Performance would do the trick too.)
Then clear plugin, CDN and , browser cache.
It’s because CF7 updated the style.css and Avada cached the CSS in theme cache(combined CSS)
if ( function_exists( 'wpcf7_plugin_path' ) ) {
$cf7_styles = file_get_contents( wpcf7_plugin_path( 'includes/css/styles.css' ) );
if ( function_exists( 'wpcf7_is_rtl' ) && wpcf7_is_rtl() ) {
$cf7_styles .= file_get_contents( wpcf7_plugin_path( 'includes/css/styles-rtl.css' ) );
}
$cf7_styles = str_replace( '../../images/ajax-loader.gif', wpcf7_plugin_url( 'images/ajax-loader.gif' ), $cf7_styles );
$styles .= $cf7_styles;
}