When I use send on a track to a bus or FX channel there is a slight audible doubling effect while monitoring even if I have nothing on the bus or fx channel. Just the mere fact that I have a send it does this. When I deactivate the send on the track the doubling goes away. It doesn't record that way. I have an 1824-C and I've tried all of the settings so it's not latency going in. Any ideas?