flush-wordpress-user-meta-cache.php

<?php
/**
 * Flush WordPress user meta cache.
 *
 * Add the flushmetacache parameter to the admin URL to flush the user meta cache.
 * e.g., http://your-site.com/wp-admin/admin.php?flushmetacache=1
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_clear_user_meta_cache() {
	// Only process if the user has administrator privileges, is in the admin area, and the flushmetacache parameter is set.
	if ( ! is_admin() || ! current_user_can( 'manage_options' ) || ! isset( $_REQUEST['flushmetacache'] ) || empty( $_REQUEST['flushmetacache'] ) ) {
		return;
	}

	// Flush the user meta cache.
	wp_cache_flush();
}
add_action( 'admin_init', 'my_clear_user_meta_cache' );