Searching the forums has not given an answer that works. I purchased a Roku Ultra a few months ago and the audio of anything played threw Plex is like a roller coaster up and down in regards to sync. I have tried direct play and disabling it and also forcing the PMS to transcode the file which seems to be better then direct play but still will have audio issues. We have Netflix, Hulu and Sony Vue on the Roku Ultra all which work just fine and have not detected any audio sync issues. This would lead me back to something is wrong with the Plex app in regards to the Roku Ultra.
I use a older high end Sony receiver which is connected form the Roku Ultra via optical cable as HDMI inputs are not on my receiver due to age. Any suggestions or a work around that actually works would be GREATLY appreciated. Plex has become annoying and useless on this thing. :-(