I also made it to the temple and expected to get teleported when stepping on the circle/star but nothing happened. I've tried to look around a bit to find something hidden or a clue how to activate the circle, but with the high rate of random battle I quickly lost the mood to do so. Random battles are all in all not that bad, but they should be concentrated in grinding areas and not in a place where you expect the player to find some hidden switch or something.