All of the different versions of the Plex app have the ability to skip forward 30 seconds and backwards 10 seconds with a built in automatic restart playback after the skip. This is true on Android, Windows, Web and Linux. The Roku version of the app skips forward and backwards in increments of 10 seconds and forces the user to press the resume button when the skip completes.
My question for the Roku support team is: Are you holding up an update of the Plex app? or, Is there an update coming at all that we do not see on our boxes for some reason?
Ron