Allowing CPU access to merged skeletal mesh on modular character

Does anyone know how to go about using a merged skeletal mesh in a Niagara effect? We are using modular characters that are built at runtime and want to be able to run a Niagara effect on the newly merged skeletal mesh.

The mesh merge is done by following the mesh merge example in this documentation. Currently when the particle effect is spawned it stays as a small ball at the origin of the mesh.

We’re able to use it on a full skeletal mesh no problem, and I think we’ve narrowed it down to allowing CPU access on the skeletal mesh. When I do the mesh merge I’m allowing CPU access on the newly created mesh, but still no luck.