XL WooCommerce Sales Triggers plugin change priority of native action hook 'woocommerce_single_product_summary' for price 'woocommerce_template_single_price'. If any theme (Premium/ Custom) not using native price action hook i.e. removed. Then add below line on code in your theme (parent/ child) functions.php to get rid of default pricing.

wcst_handle_pricing_hook_conflict.php

add_action('wp', 'theme_remove_native_pricing', 999);

if(!function_exists('theme_remove_native_pricing')) {
	function theme_remove_native_pricing() {
		remove_action('woocommerce_single_product_summary', 'woocommerce_template_single_price', 14.9);
	}
}