Depending on how much you're applying you might be overdoing the fertilizer.

I get the sense this plant may not be getting enough direct sunlight.

Thanks, I'm applying maybe 1/2 cup. Actually it gets full sun, all day. It was over 100 this weekend and I'm reading that they appreciate a little shade, so maybe too much of a good thing?

It's probably overfertilized, which damages the roots, making it more susceptible to sunburn. What I've found with basjoos is that in full sun, they tend to wilt during the day even if they are well watered. The do better in part shade. Also, they really appreciate a thick mulch of grass clippings, since it is high in nitrogen, which will promote leaf growth. I pile grass clippings on and near the base of the plant and the roots just shoot into it.