The patch is already included in the USB packet forwarder for AEP and mLinux.
If you are able to join and receive ACK’s from the network server the the downlinks are working. What is the issue you are seeing besides this warning message?
I suggest updating to an MTAC-LORA-1.5 card. The SPI version uses much less CPU on the Conduit and the accompanying packet forwarder code has a better JIT queue with feedback to the network server.