Geometry Nodes

I’ve been struggling recently to get colors applied to instances in Geometry nodes. I’m trying to apply them using Attribute Fill which works for a mesh but not for instanced geometry. Does anyone have any ideas as to why this might be happening? Each of the geometry instances have a vertex color Col channel and the Col attribute appears in the Spreadsheet. I’m assuming this just hasn’t been implemented yet.

I’m using Blender 2.93.1 on Win10.