Thank you for the feedback! Yes, we also experienced this during testing yesterday (I have no idea why, but I can guarantee it's not a virus).
The game was made on Windows 7 using GM 1.4.9. We tested it on both Windows 7 and Windows 10, and Windows 10’s antivirus flagged it for us as well.
After that, we tested it on VirusTotal, where it got a 1/70 detection rate (just like Windows Media Player and other basic programs :D), so I can assure you it's not a virus, but I don’t know why it's being flagged.
The only thing I can think of is that the game writes an INI file when saving, but even that happens exclusively in the localappdata sandbox environment, so there’s nothing to worry about.
Feel free to check it on VirusTotal yourself.
Which operating system did you try it on? I think it should work just fine on Windows 11 as well.
All the best!