Interesting. I didn’t notice that it was the Rim Light last time. In the previous two scenes I had, it was either the Key Light or the Fill Light. 
Hmm… I’ll have to take another look next time and see if I can re-produce it when it’s off. It may be that I’ll need to assign that to a different channel.
And yes, I did notice that when I was uploading the video. Good to know. 