The same issues reported in this thread. With any Plex Client above 5.6 4k HEVC stops working entirely–It will load for a minute or so, play a few seconds smoothly, grind to a halt in an artifacted mess, and then eventually I will get an error about my server not being powerful enough to transcode the stream. 1080p x264 and the bundled audio–whether it be TrueHD, DTS-MA/HD etc gets transcoded to AAC. Direct Play and Direct Stream settings are missing from options. When I downgrade back to the 5.6 client that shipped with the Shield TV everything and turn on Direct Play and Direct Stream everything is as it should be. 4k and 1080p load almost instantaneously and play flawlessly, bitstreaming the proper codec to my Denon AVR-X2300W.
Dedicated Plex server is older but it really shouldn’t matter as I’m the only user on it, and nothing should be transcoded on the Shield:
Win 8.1 and Plex Media Server/Database (always up to date) running off of an SSD.
Mapped Network drive to Synology Diskstation, forget the model number.
4x3TB Toshiba in Synology RAID
1GB Cat6 connections on everything.