[Risolto] Can't translate page, got a PHP Fatal error instead

Problem:
You are trying to translate a page using WPML, but you encounter a PHP fatal error. Specifically, you receive a PHP Warning: Undefined array key and a PHP Fatal error related to the array_merge function in the WPML plugin.
Solution:
The issue you are experiencing is related to a known error documented here: WPML 4.8 Fatal Error When Translating Pages Containing Images Without Metadata. We recommend updating WPML to the latest version available, which at the time of the response was 4.8.w. This update should resolve the error and allow you to translate pages without encountering the PHP fatal error.

Please note that this solution might be outdated or not applicable to your specific case.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 the problem persists, please open a new support ticket at WPML support forum for further assistance.