Recently many people report that there are some malware reports from users using windows defender. I can guaranteed they are false because Most of files are original file or come from trusted source.
Windows updates have made virus certification more stringent.
For a while, there will be software that reacts to virus checks.
dlsite also has a question posted in Help.
cs.dlsite.com/hc/ja/articles/1500003028021–%E3%82%A6%E3%82%A3%E3%83%AB%E3%82%B9%E3%81%AB%E6%84%9F%E6%9F%93%E3%81%97%E3%81%A6%E3%81%84%E3%82%8B-%E3%83%88%E3%83%AD%E3%82%A4%E3%81%AE%E6%9C%A8%E9%A6%AC%E3%81%8C%E6%A4%9C%E5%87%BA%E3%81%95%E3%82%8C%E3%81%BE%E3%81%97%E3%81%9F-%E3%81%A8%E3%81%84%E3%81%A3%E3%81%9F%E8%AD%A6%E5%91%8A%E3%81%8C%E8%A1%A8%E7%A4%BA%E3%81%95%E3%82%8C%E3%82%8B