I am wondering if this has something to do with the "Advanced Features | Analytics" setting defaulting to YES?
The description says "Analytics models, such as 'Students at risk of dropping out' or 'Upcoming activities
due', can generate predictions, send insight notifications
and offer further actions such as messaging users."
My students have not reported this to me, but this is not to say that the emails are not going out. If so, I too would like to turn this feature off. I am not sure what happens if I turn Analtyics off (NO), and whether other types of data (data that I might want to analyze someday) will also be turned off.
The documentation about Analytics says something about "Events." I will have to explore.
Let's see what others say.