Problem: I am experiencing an issue where editing a page in one language results in the content of the page in another language being overwritten. This is happening in both directions; editing in German overwrites the English page (and removes Umlauts), and vice versa.
Solution: Please try implementing the following fix: Add the line `define( 'WPML_TRANSLATION_AUTO_UPDATE_ENABLED', false );` to your site's configuration. This should resolve the issue of one language version overwriting another when editing.