Can't get surround sound from smart TV apps
I have a Sony Bravia KD-55X8509C TV hooked up to a Pioneer VSX-1131 AV receiver. The following problem occurs whether I'm outputting sound from the TV via HDMI ARC or via digital optical; I've tried both and got exactly the same results.
While my AV receiver is great at running surround sound from Blu-ray and TiVo, anything I play on the TV's Prime Video app comes out in boring old stereo. What's particularly odd is that the AV receiver directs that stereo sound to all 7 of my speakers at once, which is not the case when playing media with stereo sound from Blu-ray or TiVo. The same happens with the TV's YouTube app; I'm not expecting surround sound from YouTube, just 2.0 sound to my main left and right front speakers, not to all 7 speakers.
Is this an issue with the TV, the receiver, or some setting somewhere?