Contour 2 resolution and audio settings

I read your same problem on a Comcast X1 Forum (1080p setting keeps reverting to 780 [sic] when box is turned back on).  In case you didn't know, the Comcast X1 DVR is the same platform as the Cox Contour.

11/11/2015  "Pleased with its customer and employee trials of Comcast's IP-capable X1 platform, Cox Communications said it has signed a national licensing deal for X1 and has sparked a commercial rollout of a new version of Cox's multiscreen Contour..."

It's safe to assume what happens on X1 will eventually happen on Contour.

All the symptoms were as yours:  resetting to 720p, resetting to Stereo, daisy-chained AV components and, most importantly, no answers.  The only thing the Comcast subscribers could do was manually correct their settings each morning.

Disabling HDMI-CEC only provided a temporary fix because the problem reoccurred within a few days.  One of their moderators, ComcastChad, eventually noted, "We are aware of this issue, unfortunately this is fix is taking a lot longer than anyone anticipated.  It's been communicated to our support teams."

It appears to have been corrected with a firmware update.  However, the Comcast thread is 2 years old so it begs two questions.  Where is the update from Cox?  Where are the other complaints from Cox subscribers?

Perhaps Cox already pushed the update, but you didn't receive it.  Why did a technician install a new line to your house?  Perhaps your box is trying to update every night...hence its rebooting...but the update won't take.  I wonder if Cox can verify if your Contour has the latest firmware.

Perhaps this problem is more common on Cox.  I have Rovi so I can't experiment.  However, I think most people can't tell the difference between 720p and 1080i, so they're just unaware of it.  Meh, high-def is high-def.

My advice is to leave everything connected as is.  Contact Cox to either verify the version of your firmware...walk you through verifying your version...or reboot to see if the version splashes on your screen.  If you have the latest firmware, then this is isolated to your setup.  You could then exchange the box as you suggested.  If the problem reoccurs with a new box, you could then disable Anynet+...or just disable it if you don't want it...select 1080i and singly disconnect cables every night.

As far as the optical connection, I was just a stabbing in the dark.  If you have an optical connection, perhaps Contour disables audio over HDMI.  I don't know.  You could test by leaving optical connected, enabling your TV speakers and listening for two sets of audio.

Keep updating us because others may soon realize this problem.