720p on all channels in Vegas???

As Ben suggested, did you review your video settings in Contour?  How do you have it set?  Also, explain your setup.  Before the change to the channel line-up, did you notice if the channels were definitely 1080p?

Video rez is a negotiation between the TV and cable-box.  If the TV is set to 720-only, this is what the cable-box will output.

Bruce,

I don't care what the cable box is set to. I want to know the resolution of the source. 

The resolution of the source depends on the source and I'm unsure of a particular site listing the resolutions for each network.  Maybe.

However, you could refer to Wikipedia, search a network and lookup the Picture Format in the Infobox of the article.  The Infobox is the table in top right-hand corner of all articles and may contain an image of the network logo.

For example, I looked up the following networks:
• ABC:  720p
• Cartoon Network: 1080i
• CNN:  1080i
• ESPN:  2160p 4K UHD or 480i
• Fox News:  720p
• Grit TV:  480i 16:9 or 4:3
• TV Land:  1080i or 480i

Cox doesn't scale the broadcast signal; however, Cox does compress it.  Contour can de-interlace, upscale or zoom.  A 720p signal can't be upscaled to 1080p because the additional data isn't in the signal to upscale.

What I liked about the previous OS of Cox cable-boxes (Rovi) is its remote (URC 8820) could display the current resolution of a program.  Press the TV button, then Info and a li'l graphic would display the rez.  Things were just simpler & better then.