TCP Checksum offload - zeroed TcpIpChecksumNetBufferListInfo

Hi,
I am trying to implement TCP checksum offload on our NIC,
I’ve added a call to NdisMSetMiniportAttributes for NDIS_MINIPORT_ADAPTER_OFFLOAD_ATTRIBUTES in miniport initialize with all the needed configurations
But for some reason I keep getting zeros when reading TcpIpChecksumNetBufferListInfo from every TX

tcpIpChecksumNetBufferListInfo.Value = NET_BUFFER_LIST_INFO(pCurrentWlanPacket, TcpIpChecksumNetBufferListInfo);

Any idea why?