This affects quite a lot of dumps, for example also the Russian Wiktionary dump. As far as I can tell the last working dump was on the first of April. Something that I notice is that in the latest run the template namespace (NS10) is also being exported which it wasn't in the April dump, which I can only applaud, but the bug might be related to this

This would be also really useful for the German Wiktionary, where the Flexion namespace contains a lot of grammatical information. The namespace is also included in the normal articles-XML dump (however not easily usable without the expanded templates).