What could this Brown Spot be?

lol, first kid? The spot at end of cotyledon? The key here is it sprouted and there is no shell or membrane impeding the leaves. That spot will change to green as it is exposed to light, now. There is no problem here in the picture... just go easy with light, react to any stretch by increasing light et cetera... same as always. Give it a minute and all will be fine.

Looks like a tiny burn spot bro, probably from a water droplet acting like a magnifying glass under the light very common at this stage. Don’t worry, she’s fine Just make sure the soil doesn’t stay too wet and keep your light around 45–50 cm for now. The new growth will be perfect 👌

Excuse my last comment it appears iv had a brain fart.. Says soil not nutrients.. My bad sorry about that.. Light mix will keep her going for a few weeks... 👇👇👇👇💚

nothing good, but don't panic yet, the seedling are fat

Just noticed.. Hold back on the feed she can't do anything with it until she has leaves. Those cotlydons hold the energy it need for the 1st week of life or till leaves are out and roots bedded in a bit, even then just water this week is my advice..

At the end? If that's what you talking about it's probably we're the inner skin was holding the cotlydons together and got stuck at the end for a while, happens a lot sometimes it needs a little help to cone off. The 1st set of leaves will be fine.. Good luck with this grow. Much love 💚