Slow radio breaks QGroundControl comms

I’ve been using an RFD-868 radio in the field for telemetry between my drone and QGroundControl. I’ve been very impressed with the radio’s signal strength and range, but at the 10% duty cycle mandated in my region, the average bitrate is quite slow, my testing shows it to transfer around 930 bytes/second.

This is enough for telemetry in flight, but the initial transfer of parameters takes several minutes, and sometimes fails, and uploading a waypoint mission is near impossible without error messages.

I don’t mind that it’s slow, but don’t understand why it’s failing altogether when I know the radio link itself is rock solid. Is there anything I can do to improve this?