HDMI or set top box issue

[FlightCommander]

I have a Fios multiroom HD DVR that was previously connected to my Denon AVR receiver - never hadan issue with it. I just got a new Denon receiver and made the same hook up which is set top box connected via HDMI cable to my Denon AVR port for Cable. Upon starting the sytems all the right settings come on however within seconds the AVR changes to TV. This is the wrong port. I correct the problem and it goes back to working correctly but slips back to TV port within seconds. Upon 3rd time correcting the port connection via my remote it finally stays connected to the proper port and operates correctly. Had the receoiver checked and it is working just fine. The problem is now isolated to either HDMI cable (which worked fine before). Can someone please provide a solution.

Thanks.

[TomH121]

The HDMI cable is a passive device doubt very much tha it is causing the problem.

[CRobGauth]

Is it switching to a TV input?

I assume avr would have a TV output to TV.

Does it also have a TV input?

[tns2]

Probably an arc HDMI connection on A Denon.  Double check your Denon setup options and TV options.  May have hdmi CEC set to switch to TV when active.