Is there an issue with how the game is packaged that is causing the system to incorrectly detect it as being password-protected? Thanks.
From what I've seen, that's a generic message and doesn't necessarily mean it's the reason for your game being quarantined.
The staff very rarely explains why a game is quarantined (possibly to prevent malicious actors from learning how to circumvent security measures). It's possible your file was detected as a false positive, or that for some reason it couldn't be scanned, which is why that warning message is displayed to any user who tries to download it.