continue;
			}

			// Determine the effective storage key, falling back to the field name as `LLMS_Form_Field` does.
			$key = '';
			if ( ! empty( $field['data_store_key'] ) ) {
				$key = $field['data_store_key'];
			} elseif ( ! empty( $field['name'] ) ) {
				$key = $field['name'];
			}

			if ( $key && $this->is_protected_user_field( $store, $key ) ) {
				return new WP_Error(
					'llms-form-protected-field',
					__( 'This form contains a field that cannot be saved. Please contact the site administrator.', 'lifterlms' )
				);
			}
		}

		return true;
	}

	/**
	 * Determine if a storage destination targets a protected user property.
	 *
	 * @since 10.0.8
	 *
	 * @param string $store Storage location. Either "users" or "usermeta".
	 * @param string $key   Storage key (column name for "users" or meta key for "usermeta").
	 * @return bool
	 */
	protected function is_protected_user_field( $store, $key ) {

		global $wpdb;

		/**
		 * Filter the list of protected user storage destinations that form fields may not write to.
		 *
		 * @since 10.0.8
		 *
		 * @param array $protected {
		 *     Array of protected storage keys, keyed by storage location.
		 *
		 *     @type string[] $users    Protected `wp_users` column names.
		 *     @type string[] $usermeta Protected `wp_usermeta` meta keys.
		 * }
		 */
		$protected = apply_filters(
			'llms_form_protected_user_fields',
			array(
				'users'    => array( 'role', 'user_level' ),
				'usermeta' => array(
					'role',
					$wpdb->prefix . 'capabilities',
					$wpdb->prefix . 'user_level',
				),
			)
		);

		$keys = isset( $protected[ $store ] ) ? (array) $protected[ $store ] : array();

		if ( in_array( $key, $keys, true ) ) {
			return true;
		}

		// Also match custom-prefixed capability and level meta keys.
		if ( 'usermeta' === $store && ( preg_match( '/capabilities$/', $key ) || preg_match( '/user_level$/', $key ) ) ) {
			return true;
		}

		return false;
	}

	/**
	 * Form fields submission validation.
	 *
	 * @since 7.0.0
	 *
	 * @param array   $posted_data User-submitted form data.
	 * @param string  $location    Form location ID.
	 * @param array[] $fields      Array of LifterLMS Form Fields.
	 * @param string  $action      User action to perform.
	 * @return boolean|WP_Error Returns `true` on success and an error object on failure.
	 */
	protected function validate_fields( $posted_data, $location, $fields, $action ) {

		// Ensure no field maps submitted data to a protected user property (e.g. role or capabilities).