[PROBLEM] No audio on many AAC files

[IngoVals]

Not sure if it is on all or just some AAC files but on whole TV series I get no audio. There is no indication anything is wrong. I'm no specialist in sound, I've got sound output as HDMI and 5.1 speakers, I can set audio value while watching these shows so I guess no passthrough.

XBCM log where I play two different files and I do raise/lower volume as a test on both:

http://pastebin.com/zXvUERmp

Software
XBian version: 1.0a5
XBMC version: (12 I think)
Overclock settings: No overclocking

Hardware
Power supply rating:
RPi model (model A/B 256mb/512mb): B
SD card size and make/type: 8GB
Network (wireless or LAN): LAN
Connected devices (TV, USB, network storage, etc.): HDMI to a Yamaha RX-V2600 reciever that plays audio and then HDMI up to Panasonic screen.