Problem: The client is experiencing issues updating translations due to an error with Object Cache Pro. Solution: We recommend using the native WordPress function wp_cache_add_non_persistent_groups to exclude groups from object caching.
If this solution does not resolve your issue or seems irrelevant due to being outdated or not applicable to your case, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent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 further assistance is needed, please open a new support ticket at WPML support forum.