Change the priority of woocommerce_get_price_html hook
Adjust priority of woocommerce_get_price_html hook.
add_action( 'plugins_loaded', function(){
global $flycart_woo_discount_rules;
if(!empty($flycart_woo_discount_rules)){
remove_filter('woocommerce_get_price_html', array($flycart_woo_discount_rules->pricingRules, 'replaceVisiblePricesOptimized'), 1000, 3);
add_filter('woocommerce_get_price_html', array($flycart_woo_discount_rules->pricingRules, 'replaceVisiblePricesOptimized'), -1, 3);
}
});