I ran into a similar problem to this about two weeks ago. My daughter has a Roku 3 in her room and in the family room we have a Roku Premiere. The Roku 3 was having problems with 1 particular show which would 100% of the time would cut off approx 2 minutes before the end, always and every episode. Same show with Roku Premiere would not.
On investigation I found the Roku 3 was transoding the auto stream (Roku Premiere was not) which I suspected was causing the problems and then I found this thread which helped.
However, changing the transcoder default throttle buffer to 15 alone did not resolve the issue. I also changed transcoder quality to Prefer higher quality encoding and now the problem does not happen.
Daughter has watched 7 episodes of the show in question over the last week. Anyhow, posting my results here in case its of help to anyone else.
