yellow leaf

Nothing to worry about A single yellowing lower leaf around week 3 usually just means it’s an older one that’s being used for stored nutrients totally normal as the plant focuses on new growth. Just make sure your pH and watering schedule are consistent, and check that the EC isn’t too high or too low. If it spreads upwards, then it could be a mild nitrogen deficiency otherwise, you’re all good

Plants will shed their old leaves they are not longer using or want to get rid of. That was its its first set of true leaves that had 1 finger. I would not worry about it.

if it is isolated, i'd ignore it. That's a single-bladed leaf - the 2nd set the plant grew, i.e. one of the oldest leaves and not even a mature leaf for lack of the proper vocabulary. These often get shed, like cotyledons, by the plant and no other symptoms will be seen. If it is progressing anywhere else, take a different approach. From what i see, the other foliage is healthy and a uniform shade of green. Let it suck it down until a very gentle tug causes it to fall off. Do remove from growing area. Decaying leaves are a disease vector long-term... no worries letting the plant suck it down, though. 23 days with side branching as thick as that, secondary branching off that, too? think this is measuring from the taint, lol. The others look closer to what should be.