Issue with WPML 3.1.5

Hi,

I'm trying to update WPML on my website, but I am running into what seems to be a compatibility issue with Atahualpa.

My website is in french, with english translations for pages and posts. Everything seems to be working perfectly, except for the posts archive page in english (i.e. for example http://mywebsite/en/blog/2007/12/) which only displays a blank page (empty source, I don't even get the wp-admin header bar when I'm logged in).

With WPML 2.7.1, the site is working. With the default Twenty Fourteen theme, there is no issue. This problem happens when I use Atahualpa. I was using the 3.7.11 version, I tried the 3.7.15 and 3.7.18 versions, the issue remains. I set WP_DEBUG to true but no error whatsoever gets logged.

Can you help me troubleshoot this ? I'm sorry but my test site is not accessible through internet.