These results are not in the language I have my browser set to, so maybe it is filtering based on language.

No if you change the language to Russian, it still shows the single result in English. Changing region is the only way around it.

That's not correct. You can show the proper results without setting the region. Do this by adding an empty token that doesn't get stripped, "https://duckduckgo.com/?q=vk+%22%22". That also shows the results list.

Yes. I manually put Region=Russian in the comment's URL.(kl=ru-ru)

So you get russian results.

Searching vk "" gives the results, no matter the language or region settings