Reported for: WPML Multilingual CMS 3.6.2
Resolved in: WPML 3.6.3
Currently, there appears to be some issues with parent-child relationships between custom post types in the plugin Types, when WPML is used.
Saving a post that has such a relationship may lead to loss of data.
We are currently working on resolving this issue.
As a very crude workaround that will prevent the loss of data in old posts you can edit the relationship.php file found in the ../wp-content/plugins/types/library/toolset/types/embedded/classes/ folder.
Comment out the row 305:
$updated_id = wp_update_post( $post_data );
Please note that this is only to prevent loss of data in already existing posts. This will not have an effect on new posts that you create. It is recommended to wait for the official fix.