Retarded plant

100% of the time when seedlings growth is stunted it's overwatering, humidity, and temp being off.

Are you sure it's not looking like a two and a half week plant instead of two and three quarter weeks? LOL You're splitting hairs a bit. Some plants, even within the same strain, develop at different rates sometimes. Tons of factors can cause this, not all being related to the genetics of that particular seed. Maybe that pot was slightly overwatered or sitting in a cooler corner of your space, thereby stunting root development early on. Maybe it sits at the edge of your light footprint so the light it receives is weaker than the others, etc.

Could have been underwatered in the early stages, sometimes this can lead to small growing plants with small leaves.

Could be a shit-ass plant. Are the top couple nodes stacked super tightly? If so, reduce light. If stunted it could take a minute to snap out of it.

Dunno, looks fine to me tho..