What could be a reason thst two of my plants have ...

I agree with @souljasam, no worries about the very first young leaves looking "droopy", that's perfectly normal (check any grow here running from seedling and you'll find it almost everywhere). Also the technique for watering habit which souljasam described is great, I use it myself, though it takes some experience as it is based on feeling and also the plant is getting heavier in time :) BUT what concerns me is the amount of water you have in the Grow Conditions (0.38l/day) that's way too much for soil-based grow even for much bigger plants. Try to keep the soil moist but not wet (it should be nicely soft and there should be no liquid visible when you lightly press the soil). Once the plant becomes bigger it is usually good to water whenever you feel the top ~1cm of soil is dry. When you see the edges of soil start getting separated from sides of the pot, like if the soil was shrinking, it is last minute sign and you should water immediately. Good luck and happy growing!