WPML All Import - Importing a 3rd language resets content in 2nd language as the default

Overview of the issue

When importing content in a third language using WP All Import and the WPML All Import add-on on a site built with Gutenberg blocks, the content imported in the second language is reset and overwritten with content from the default language.

Workaround

Please make a full backup of your site before proceeding.

1. Temporarily deactivate the WPML String Translation add-on.
2. Import the content in your default and secondary languages.
3. Reactivate String Translation.