It's not current information
To the best of my knowledge guys the new Octavia has not been tested. It now shares the same chassis that the Yeti does and the Golf 5/6 range. The Yeti blitzed the euroncap when it was done recently so i can't see why the new Octavia wouldn't be in the same position.
The euroncap and the ancap both place their crash test info on a 2004 vehicle which was the old mark 4 golf platform (4 metres of laser weld) as apposed to the new generation platform (128 meteres of laser weld).
Being very new to the brand and still finding my feet I could be way off the mark here but that could explain the poor 4 star score, outdated info??