Getting too much light. The sets of leaves are way too close together. More so on the left plant. Reduce light and it may take a few days or even longer to snap out of it, if stunted. Existing nodes won't spread out much but it will slightly. Judge new light intensity based on new node growth, once it kicks back into gear. You don't want lanky stem between nodes, but you do want it to develop. The leaves shouldn't so tightly packed. Reducing light will improve growth rate. Should help them darken back up to a healthier green, too... see how that plays out before adjusting fertilizer. If you already adjusted upward, consider reverting until you get a more normal growth pattern to distinguish between nute-related or light-related paleness in plants. Could be both, but you tackle each possbility 1 at a time so you don't mistake cause and effect. Whether you start over is up to you. I don't think it'd save you any time. These may take a bit to reset, but it'll be much farther ahead than a seedling. I'd definitely correct course before restarting, but each to their own.