Track matte not working in bodymovin

Hi. I'm having an issue with a single layer in an animation which I am exporting through bodymovin.
I am using multiple track matte layers that sit underneath each shape layer of the penguin. The pink outline is the shape layer I am using with inverted alpha matte layers. This all plays perfectly in after effects but when I export out through bodymovin, the white belly does not mask (see screenshot on beige background).

Is there a way of sorting this? I have tried auto tracing the layer and masking it, precomping the layer and masking, adding the white belly layer into the body layer so that it moves with it, and parenting the white belly layer to the body and masking. I have also tried putting the mask on a solid layer, and also creating a mask that is the opposite shape of what i've drawn, covering the area that the penguin is diving.

I'm using After Effects 25.4. Any help would be so greatful.

Thanks!