Hmm, interesting, could be.
I went back to the closest possible time from before the brown fingers and it was about 2 and a half hours prior
View attachment 4614993
Between this before photo and the brown finger from what I could see Keffals only smoked 1 cigarette and it was right after this photo was taken, and even then the finger didn't look anywhere near that brown. So I think it can't be from the 1 cigarette that was smoked.
Keffals takes a 14 minute break after the talk with Xanderhal and their finger now looks like:
View attachment 4615041
The above photo is about 5-10 minutes after the initial "brown" finger photos I took, during which time Keffals has wiped their finger along their lip etc multiple times, so whatever it is, it seems to be coming off?