I have my KD65 AG9 connected with Sony's high-speed HDMI connected to an Onkyo NR696 receiver through ARC. 

When I watch a movie from an external USB HDD, sometimes the sound disappears. E.g. last night it worked well for first ~1,5 hour, then disappeared every 10 mins. If the sounds disappears, i can get it back by (i)  turning receiver on/off first (ii) rewinding/forwarding the movie, so it reloads. The sound is set on passthrough, and the receiver rightfully plays it back as Dolby Digital or DTS depending on the source.

Both devices are updated to latest firmware.

Anyone experienced this? Ideas how to resolve? would hope that Sony's top model is not exposed to a continuous restart...

thanks!