Spanish first and audio our of sync

We sat down the other night to watch one of our movies. Two things happened:

  1. The spanish audio track played by default. We had to manually select the other audio track.
  2. The audio/video was out of sync almost straight away. We switched to kodi on the same xb1 and the audio/video played perfectly.

Tried the same movie from the same plex server on my shield tv and the English track played by default and the audio/video was perfectly in sync.