[Résolu] Fixing gallery so it shows on translated pages

Background of the issue:
Gallery vanishes on translated page.
Works on one translation and doesn't on other.

The issue can be seen on this page: lien caché.

Symptoms:
I expected to see a gallery like on other versions, but instead, I got no gallery.

Questions:
Why is the gallery not showing on the translated pages?
How can I ensure the gallery appears on all translations?