When painting vertex color on a speedtree mesh, saving vertex color to the source mesh does not work

I’m trying to blend some textures using vertex color on a speedtree mesh in my project. When attempting to paint vertex color, it correctly applies the vertex color to the instance. However, when I hit the green check mark to “propogate instance vertex colors to the source meshes”, it does not correctly save.

Doing the same process with a standard static mesh works correctly. The source mesh recieves the updated vertex color.

I got a same problem.