With several others all being fed off the same system, I wouldn't worry about it. As long as the roots look good, there is unlikely to be some isolated issue with one plant as opposed to the others. That little wilting can most likely be attributed to "thirsty", and should alleviate itself in a short period of time. As wheels619 said, pay attention to the roots, just to be on top of things, if your roots look good then it is likely nothing, but it could also an early indicator of something worse.