Can you try again please? And in an in-cognito window?
I just tried it
and it works for me: https://test.wikidata.org/wiki/Q649
We've had some
issues with local store though.
Weird, does work for me incognito but not when logged in.
The datatype changes but the value type stays string.
So depending on
what they use they might need to be adapted.
RDF export seems to be fine, except that we need to update OWL and docs
for new types, I'll check pywikibot a bit later.