At about 8:50 PDT this morning, 2 out of 3 MacBooks in our household restarted at the same time (about 1 minute apart). What happened is I left the room for about 5 minutes, and when I came back I saw the "you restarted because of a problem" message. I logged in as usual and started to try to find why. Then I heard two startup chimes from the other two computers. I checked those, but only one laptop actually restarted. These two computers were closed when the chimes occurred.
My question is if there is any force-restarts/updates by Apple. If not, why would this happen and is it due to some sort of network-propagating virus?
Note: I don't think the restarts were kernel panics, as I wasn't shown the grey screen of death.
The computers that restarted were on high Sierra. The one that didn't restart was on Sierra.