VLC for iOS v278.1 on iPad iOS 10.3.1
If a video is played from the "root" level ("all files"), the |<< & >>| buttons work as expected, skipping backwards or forwards 30 seconds at a press. If the same file is moved into a user-created folder and played, the buttons don't operate correctly and instead take you back to the start of the video.
Moving the video back to the "root" level & playing, the buttons again work correctly.