some strains look just like this. new growth comes twisted then opens up and gets a flat shape.I'm growing a plant that was like this in veg,Congo. If those older leaves started twisted too,there is not a problem.Plant looks very nice.And I don't think it is a problem, I'm experiencing the same thing with my plant and it is now flowering really well.By the way,it grows like this with every seed so I can confirm this is plant's characteristic. Long story short ; no problem.