Have a look at this gif:
(MP4 version: https://i.imgur.com/XRSHj4V.gif
What you can see is the following:
1. I search with an English keyword with activated language filter.
2. As the filter is set to "Germany" most results are in German. So far that's okay as it is what I expect.
3. I switch the filter off.
What happens: The results are still the German ones, although the filter is set to "off".
What should happen: Display English/international results.