[Resolved] PHP Error

Background of the issue:
I am using WPML on my site hidden link. I noticed a PHP error while using the query monitor. The error details are as follows: Level: All, Message: rtrim(): Passing null to parameter #1 ($string) of type string is deprecated, Component: Plugin: sitepress-multilingual-cms, Count: 3, Location: wp-includes/formatting.php:2831 rtrim() wp-includes/formatting.php:2831 untrailingslashit() wp-includes/formatting.php:2816 trailingslashit() wp-content/plugins/sitepress-multilingual-cms/classes/url-handling/class-wpml-include-url.php:23 WPML_Include_Url->filter_include_url() wp-includes/class-wp-hook.php:326 apply_filters('style_loader_src') wp-includes/class-wp-styles.php:412 WP_Styles->_css_href() wp-includes/class-wp-styles.php:221 WP_Styles->do_item() wp-includes/class-wp-dependencies.php:137 WP_Dependencies->do_items() wp-includes/script-loader.php:2284 print_admin_styles() wp-includes/class-wp-hook.php:324 do_action('admin_print_styles') wp-admin/admin-header.php:132

Symptoms:
PHP error: rtrim(): Passing null to parameter #1 ($string) of type string is deprecated

Questions:
Is this PHP error something that slows my site down?