Onkyo TX-NR676. HDMI Out Main+Sub, Signal Drop Issues

I have an issue where my HDMI source will drop randomly. So I posted in projectors first as I thought it may be a projector thing.. However, it seems to be the receiver.

In my receiver settings the Input/Output Assign > TV Out / OSD > HDMI Out > Main + Sub, seems to be the issue. My projector is on Sub, and if I switch it to Sub only for HDMI Out, it seems to miraculously fix the problem...

Anyone know what the deal is?

My other post - [HDMI Dropping: BenQ x500i, Onkyo TX-NR676, Blue Rigger 40ft HDMI : r/projectors](https://www.reddit.com/r/projectors/comments/1jsxbk4/hdmi_dropping_benq_x500i_onkyo_txnr676_blue/)