Leaves turning upside down?

i just changed out the reservoir and phd it and added the nuts, in the maybe 45 seconds the plants were not in the reservoir one of the smaller ones leaves flipped upside down... its mildly drooping also, none of the other plants seem to have this problem but im starting to be concerned about its health. any help or tips or suggestions as to what may be causing this and how to fix it? BTW im still a noob so go easy on me

If it is just that one leaf and happened that soon, are you sure that you didn't accidentally hit that leaf? Or possibly a pet played with it?