lost attributes with WPML

Hello
My site is multilanguage with WPML.

I used to have NO translations for Product Specification Table/Group/Attributes.
I created 1 table, 3 groups and some attrs each.

They were available in backoffice for every language. No need to translate.
In product edit I saw the tables (1). If table selected, I saw the groups. Clicking on 1 group I saw the attributes and the value fields.

Switching to another language, the same, but I could fill the fields with different values.
And so in the frontoffice I could see the different values per each language.

Now suddenly, I do not know why, if I edit one of the products that used to have specs table filled in any language, it shows
1. the preselected table (ok)
2. the correct groups for that table (ok)
3. NO ATTRIBUTES and the text: “No attributes defined yet”

The problem is I already edited many products in 8 languages, and the postmeta json is there in the DB but it does not show in backend. In frontend if I load and old product in another language, I see the spec table html output 🙂
Then, if I click “Edit the product” the specifications box says: “No attributes defined yet”

Note: specs-table, spec-group and spec-attr are all set as “Translatable, use default language if current language is not available,

Any hint about the cause and the fix?