Polylang support with Shortcodes / NextGen gallery?

I am using Nextgen gallery to insert a gallery into my pages. I have an English page and a Spanish page, both with separate galleries for each language.

On the Spanish version the Nextgen gallery doesn’t work as intended (it’s showing only the correct alt tag on the first image but not on the rest), but when I change the page to English it does work.

When I use Nextgen gallery it inserts a shortcode into the page – could there be something in the settings that’s affecting the shortcode if the language is set to Spanish. The fact the gallery shows at all means it must work, but could there be something in the language that’s affecting the shortcode to not work at it’s full capacity?

Thanks in advance.