What happened to skipping?

So I used Plex on my Samsung TV (2015 model), and I got a Shield because Tizen.

However, I'm a bit stumped as to where skipping went. I can fast-forward when watching movies, but it seems I can't skip (15, 30 seconds or whatever).

I see I can jump straigh to chapters, but that's of limited usefulness.

It should be noted I'm using the Logitech Harmony to control the Shield, have I just messed up the mapping?

edit: I should add that the Plex server is running on my local FreeBSD box (plexmediaserver-1.0.3.2461).