TBH, those look like a combination of things. My guess is a bit of nutrient burn (which is normal the way the roots float in the water) but also some water on the leaves that maybe burnt them. I wouldn’t be concerned with a few leaves like that. However now is the point to make sure all your bottles are dispensing and do a pinch test (test each hose into the bottle, in through the metal and anywhere EASILY accessible) and pinch or adjust the tip ever so slightly incase a blockage occurred. This was my recent problem on my plant and i caught it early enough it bounced right back.