It doesn't seem to happen with beta 43, I've even scanned the /Program Files/GPSoftware/ folder twice with the Windows Defender and there aren't any detections.
That probably doesn't say anything about beta 43 vs. any other one.
I never saw any of this until a couple of days ago. I'd been running with 42 without any problem. All of the sudden Monday morning, it was a threat that wasn't allowed to run.
Beta 42 hadn't changed (I don't think). I assumed Defender's definitions had been updated. I restored system from a backup created the previous day. Everything fine. I updated the Defender "security intelligence". Everything still worked.
I did some more experimenting without coming to any conclusions about what combination of factors was OK and what not.
All I'm saying here is that I don't think one can conclude that installing a new beta "fixed something",