Thanks Helson and Xenonman. Yes, I figured it was a handshake issue. I am trying to figure out if it is the TV or the Marantz. Turning the TV on first, sort of defeats the purpose of the pass-through. The cable box is on all the time -- it's the main DVR box. The Marantz is either on standby or "on" and when "on" then all works fine. If the TV is on and I turn the Marantz to on and back to standby, the handshake is successful.

It is almost as if the Marantz isn't really providing a hard-connection pass-through mode to the cable box after some time, but turning the TV on the first time wakes something up so it always handshakes properly the second time.

I have no more than 10-ft in-wall HDMI cable from the Marantz to the TV and a 1.5-m cable from the Marantz to the cable box. It should be easy to change the short cable. I'll try that first.