I get this message, and I don't like it, as TG is legit. The antivirus of KPN has blocked access, it says. Luckily I already have it installed on another machine, but I don't know how I could undo this (if needed).
This build is only available to alpha testers, so it has very limited circulation. That may have something to do with it, but we'll need to watch what happens when it is released more widely.
I had the same problem with Avira. The program put all of the latest .exe files into quarantine showing the same virus signature like Ulco's program. Luckily I could restore the files.
Oh yes, I should have posted in the alpha section. Interestingly, it has been sitting on a usb stick for a while, which I have into that online machine off and on, and only now it has been scanned apparently.