I have to say, I think MB developers need a bit of a wake-up on this.
No doubt the majority of users are just not reporting it, assuming its ok, or not caring.
I have taken earlier steps twice, re-installing the MB3 app, doing restarts etc etc.
My current update package version is: 1.0.3871
Yet, the "Real-Time Protection turned off" message still comes back. It all works fine after the re-install etc for a few days, then m-BAM ... same problem.
Some things I do that may help in recreating this ... I often Hibernate (Win 10). My internet takes a while to connect once I login for some reason - seen this in last few months. It's cable and on all the time, but when Windows logs in it can take a few minutes to get web results. A bit strange, and may be related to the issue. I mention it as testers may be missing something like that.
I have now added the exclusions, can't restart now, but will soon and see if that fixes it.