That Windows machine you are using wouldn't run a virus scanner like AVAST?
AVAST offers a feature called RealSite that will inject additional DNS queries to a "trusted" DNS server (run by AVAST) in case something goes wrong with normal DNS resolution, see Hilfe: Windows löst Hostname auch ohne PiHole auf? - #26 by Chris80 (though German, it also contains a short solution description in English).
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