When client performing the callnat is MF with NAT/NSC v9.x and it is doing the call to a RPC server running under Windows with only NAT (no NSC) the RPC call will still complete normally when Windows NATv8.x is being used, and only fails when Windows NATv9.x is installed.
This further suggests that ICU is NOT required to complete RPC calls and that it is only some incorrect or incomplete check on the client (MF) side artificially preventing the RPC callnat to complete.
Additional information:
When client performing the callnat is MF with NAT/NSC v9.x and it is doing the call to a RPC server running under Windows with only NAT (no NSC) the RPC call will still complete normally when Windows NATv8.x is being used, and only fails when Windows NATv9.x is installed.
This further suggests that ICU is NOT required to complete RPC calls and that it is only some incorrect or incomplete check on the client (MF) side artificially preventing the RPC callnat to complete.