In case anyone was interested, I found a workaround. On the dynamic mesh, use the node “apply mesh mirror” to append a mirrored copy of the mesh next to the existing mesh. The mirror will have a correct normal map. From there, you can apply a plane cut node to cut off the original non-mirrored mesh, and a ‘translate mesh’ node to reposition the mirrored copy back to the proper origin. It works, but I’m on the fence about on whether to call this a “solution.”