Hey guys.
Thanks for the feedback. The problem is definitely related to a 5 point patch, and it does show up in a full choreography render with white lights. My model & materials were built in v12. When I tried to load the model in v11.1, it would not load properly, so I did not try rendering it in v11.
The problem appears to be related to the 5-point patch somehow retaining some settings of a material previously applied to the patch. I noticed this same problem in another of my models. In the model in this post, many of the blue 5-point patches render w/ the orange toon-line from another material in this same model.
In my other model, a skin-tone 5-point patch is rendering a red toon-line from a red material in the same model.
I managed to fix the skin-tone patch by deleting the points and reconstructing them from the scratch and applying the skin-tone material again. I'm going to try the same with this model.