Rhino Sub-obj materials are not exporting with datasmith

hello
in rhino you can apply a material in sub-obj mode (a face of a cube for example) but when importing it into unreal the objects with two materials that one of them is a sub-obj material are imported into unreal with only one material for the whole obj.
im useing ue5 preview 2 with latest datasmith for rhino
is this a bug or datasmith doesnt support this feature yet if so is there a plan to be developed?
or maybe this a limitation on rhino’s end?