There are several threads discussing audio issues with IgniteTV. Here are a few comments:
1. With the appropriate audio setting in the box' user menu, you should be seeing (er hearing) DD5.1 for live programming and on-demand programming.
2. Any recordings you make in the cloud will be DD5.1, however, they will be improperly encoded and only have signals for the LF & RF speaker channels. The only way around this is to choose the "other" setting in the box, so that you can then invoke DPL in the AVR to give you surround sound. This has been happening for many months, perhaps even a year.
3. This assumes a direct HDMI connection from the box to the AVR and then to the TV. If you're connected directly to the TV and then via optical to the AVR, then the TV needs to be set properly for DD5.1 (or raw or bitstream, etc) in the TV's audio menu. Also, some TVs may not pass DD5.1 to the AVR. See point 4 in the following FAQ:
1. If you're only listening to the TV speakers, it shouldn't make any difference in audio quality whether the TV is receiving PCM or DD5.1
2. It's possible that the HDMI "handshake" that takes place between the TV and the box every time the TV/box is turned on is overruling any box audio settings since the handshake senses a TV and sends PCM, two channel audio, which is perfectly fine for a TV.
3. Have you checked a number of different channels?