when you are in fullscreen mode, if you don't pause the video, but you simply touch the Back button while the video is running, the AR view will keep playing the video from where it was.
However, if you first Pause the video, and then you exit fullscreen (via Back button), then the 3D view will show the icon instead of the last frame;
the reason for this is in this code (in VideoPlayback.java, see onResume() method):
// Reload all the movies
if (mRenderer != null)
for (int i = 0; i < NUM_TARGETS; i++)
i, mMovieName[i], mSeekPosition[i], false);
i, mMovieName[i], mSeekPosition[i], mWasPlaying[i]);
Since you have paused the video while you were in fullscreen mode, when reaching the code highlighted in bold above, the mWasPlaying[i] variable will be false;
as a consequence, the requestLoad() method will handle this as if the video must be reloaded and restarted from zero; that's why you see the icon instead of the last frame.
If you want to achieve what you describe, you will need to change a bit the code in mRenderer.requestLoad()...