if it is still growing and no signs of yellowing, i'd stick with it a tad longer... the longer that lasts, the more likely it was toxicity, obviously. twisting of leavs is never good. A little warping from heat, meh.
otherwise, mutant?
Stick with it.. i bet it rebounds of the two likely possibilities. If nodes are not spacing out at all, raise light a bit. (not from pictures, you'd have to give her a look and decide in real life)