Server Version#: 1.13.5.5291
Player Version#: 2.18.3.70
In addition to the persistent buffering problem (approaching… what … two years to fix this?) Plex for XBone also has a Subtitles problem. When selecting SRT Forced or other subtitles, then returning to a video in-progress and un-pausing, Subtitles might appear once. Then never again. I have been unable to reproduce a situation where this either consistently fails or consistently succeeds. Sometimes, pre-selecting subtitles before playing a video works.
Frankly, with so many critical bugs on the XBone I’m giving up – have setup an AppleTV and have made that my primary Plex device. The Xbox One plex agent is a total disaster.