Philip

Problem:
If you're experiencing a PHP fatal error in your WordPress admin when editing content that uses ACF Pro Flexible Content fields, particularly after updating the ACF Pro plugin, this might be due to ACFML interacting with ACF fields. The error typically occurs during Flexible Content value loading and is more prevalent in translated languages than in the original language.

Solution:
We recommend checking the WPML translation settings for your ACF field groups. Specifically, ensure that fields such as Relationship or Group fields are set to 'Copy' or 'Copy Once' instead of 'Translate'. Incorrect settings can lead to inconsistencies and errors across different languages. You can find the recommended settings on our documentation page: https://wpml.org/documentation/related-projects/translate-sites-built-with-acf/recommended-custom-fields-translation-preferences-for-acf-and-wpml/.

After adjusting these settings, try making a small change on the German Options page and save it, then save the secondary language options pages. If the problem persists, it might be due to a more complex issue such as leftover data from a Flexible Content field that no longer exists.

Please note that this solution might become irrelevant due to updates or specific configurations in your setup. If these steps do not resolve your issue, or if you find the information outdated, we highly recommend checking related known issues at https://wpml.org/known-issues/, verifying the version of the permanent fix, and confirming that you have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 necessary, feel free to open a new support ticket at WPML support forum for further assistance.