I see two nested comps in your screencap – “front hand” and “head primary”. Assuming that “head primary” contains the layers that make up the jaw area, you have to go into the precomp and set the Blending Mode there. Also, assuming that the jaw animation is done in the master/parent comp, you have to enable Continuously Rasterize for the “head primary” nested comp – this ensures that the Blending Mode in the precomp is carried over.
Hopefully, the continuously rasterize switch doesn’t introduce issues. If it does, then see if you can bring everything from the precomp into the master/parent comp – in other words, do everything in the master/parent comp.
HTH
RoRK
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