url broken – drops category

After updating my linked posts aren’t working anymore. I have a custom post type and the taxonomies (categories) properly link to each other in all the languages.
Example: http://sithoniagreece.com/halkidiki/accommodations/ properly links to http://de.sithoniagreece.com/halkidiki/unterkunft/

But any individual post just drops the category from the url, and thus produces a 404.
Example:
http://sithoniagreece.com/halkidiki/sarti/accommodations/camping-armenistis/ links to http://de.sithoniagreece.com/halkidiki/sarti/camping-armenistis/
This produces a 404, since the category (“unterkunft”, which is the equivalent of “accommodations”) just is dropped from the url.

I didn’t have this problem before. But I recently updated both your plugin and WordPress, so it must have been something in that. Could you please check it out?