I know I am really late, but I just wanted to say this:

Apparently, the issue has something to do with the way PyInstaller compresses it, which is why it's marked as a virus. I have honestly experienced this issue twice before and it's extremely frustrating.

Fortunately, there is a way to get it whitelisted, though. If you visit this link, you can get your software whitelisted by Microsoft. Although it is a long process, depending on how important your application is it may be worth it. All you need to do is fill out a form and you should be all set.

I really hope this solution helped you, even though I saw this pretty late. Still, I figured it could be of at least a little use. Anyways, I hope you have a good rest of your day!