It's a safety thing to prevent unwanted feedback loops.I'm new to using the send and return blocks so I don't know if it's supposed to be this way but....when you add a return block the return level is set to 0. I spent a bit of time searching for what I had done wrong before discovering this ridiculously simple answer. I'm not sure if anyone would want the default return level to start at 0. My guess this is just a one that will be addressed in the next firmware. Of course everything sounds fab.