Well, we are all crazy, so that doesn't matter.
So, when I say lay 2 eggs in one day, I would think that the egg cycle was just shortened a little. So, the normal egg cycle is around 25 hours. So, with pullets and their system not completely worked out yet, then, that cycle could be a little shorter at times and you get 2 eggs in a 24 hour period. Then, most times they skip the next day. And, they don't do it regularly, but it can and does happen.
So, I don't know about laying one within 30 minutes. But, I think it could be possible. So, watch her and see what happens. Other than she seems to be laying an extra egg, she seems to be ok?