Known issue

Problem:
The client was experiencing an issue where the Spanish translation of their WordPress site using WPML was not working, displaying an error: 'Uncaught Error: Unknown format specifier "S"'.
Solution:
1. We asked the client to increase the WordPress memory limit by adding the following code to their wp-config.php file:

/* Memory Limit */<br />define('WP_MEMORY_LIMIT', '256M');

2. We recommended applying a workaround described on the WPML erratum page regarding PHP 8 compatibility issues, which could be related to the error the client was facing. The erratum can be found here: https://wpml.org/errata/php-8-php-fatal-error-uncaught-valueerror-unknown-format-specifier-in/
3. After reapplying steps from the WPML documentation on resetting the plugin data, the issue was resolved. The relevant documentation can be accessed here: https://wpml.org/documentation/getting-started-guide/language-setup/deleting-languages-and-plugin-data-by-doing-a-wpml-reset-on-your-site

If this solution does not resolve your issue, or if it seems outdated or irrelevant to your case, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have installed the latest versions of themes and plugins. If needed, please open a new support ticket at WPML support forum for further assistance.