Injectors like this are frequently flagged by antivirus software as "Potentially Unwanted Programs" (PUPs) or malware because the same techniques are used by malicious software to hijack legitimate processes. If you are using this for modding, ensure you are downloading it from a trusted source to avoid bundled malware.
The "V3" iteration of this tool often refers to the latest codebase found on platforms like GitHub (masterpastaa) , which introduces several stealth-oriented features: face injector v3 work