Given that I'm having hard time trying to figuring out what those bulliform cells are, I agree on water.
I knew the soil wasn't dry. This soil has a lot of defect but it keeps moisture well. Then, as you say, I know that when plants are thirsty and you give them water the foliage suddenly gets up. Those leaves are still floppy, and the soil is really wet.
It maybe normal on some kind of foliage, because I don't see anything similar on DLs like Stella de Oro or Litlle Show Stopper. I have a neighbour that had Hemerocallis Fulva sp. in her garden, I will check how that foliage behaves. If she still has it because I didn't notice for now. I will say to the hybridizer that water didn't change a bit in those leaves.
