Custom Normals lost during animation

Hey. Having an issue with the transfer Data modifier and custom normals during animation. When the mesh is static the normals are fine, but once it deforms they are lost.

Custom Normals animation test.blend (634.3 KB)

Are you sure you posted the right file? I can’t find data transfer modifier on any object. And by default data transfer modifier works in global space, did you try switch it to local?

The data transfer modifier was already applied to the deformed mesh. The one on the right was used to transfer the normals.

Go to rest pose and the seam should disappear. However; while being deformed it returns.