"Had it been launched at all that day? or not at all?"....

Probably from the day before.....I don't know if I left it running. 

But it didn't show in the Taskbar as being active....i.e. it wasn't minimized.
I only became aware of it when I saw the Task Magager icon partially green,
indicating a significant amount of CPU resources were being used.

I'll keep an eye on it......maybe it was a fluke.