I can confirm the wrong channel mapping on 5.1 sound. I was so happy to discover today there was finally a ps3 app so I paid for premium just to get it. I just sat down to watch a movie and said to my girlfriend., "Is it my imagination or is all the dialogue coming from the front right speaker?". I then tried playing the same movie using Plex with the ps3 the old way (through the video media servers section) and the same movie played just fine with the correct channel mapping. I really hope this issue is addressed soon.
Much of this has been discussed and/or acknowledged by Plex. Please use the correct forum: [Plex for PlayStation](https://forums.plex.tv/forum/153-plex-for-playstation/)