What am I getting this ? I don't considere a program trying to log into my Windows account a normal behavior
If you look in the File>Preferences>Activation menu you'll note your license is tied to both the email account used to download the software, and your computer's unique ID number.
I believe when logging in Hitfilm just does a quick check in with the registration server to verify your account and trigger the Update dialog (if needed). That should be it.
I'll tag in a couple of Staff who should have more insight. @TheBenNorris @philipwesson