CGI, my TV, or my tired eyes--Funny

I just watched this movie again last night. A small funny item.

Remember, Bruce Dern's character is missing his front teeth. There is a scene near the end of the movie when his son is driving him and he is asleep with his mouth wide open.

I swear there is some slightly jumpy CGI making his mouth black because they realized his teeth were showing. It is too black, and it appears to have a bit of a jitter where the black meets his lips. Now one could argue, why would they want to do that, as he would be wearing his false teeth in context of the movie. Not sure I know the answer to that.

Maybe it's me, but would love others who have this streaming or own a copy, or are going to watch it to take a close look and see if they see what I thought I saw!