Overview of the Issue
In WPML 3.9.0 version, there is a problem in some cases when the site’s default language is not English, with the String Translation and the translation option for the custom post type slug. If you have a custom post type that has a translated slug you might encounter this problem.
WooCommerce Products can also be affected if the slug for Products is translated.
The issue results in a 404 Error Page to be shown or the product to not be available in that language.
Workaround
This issue is fixed. Updating to the latest version solves it on your site, so you only need this workaround if you can’t update yet.
This issue will be resolved in the 3.9.1 version of WPML.
As a workaround, you can edit the slug-translation/class-wpml-rewrite-rule-filter.php file, found in the ../wp-content/plugins/wpml-string-translation/classes/ folder.
Replace the following code:
if ( $new_match != $match && $display_as_translated_mode )
with this one:
if ( $new_match != $match && ( $display_as_translated_mode || $current_language !== $default_language ) ) {
Afterward, you may have to visit SettingsPermalinks and click Save Changes without making any changes.
