Rust looking stains on leaves

Plant is 2.5 weeks old. Growing in Gaia Green living soil blend 1-0-0 with perlite. I overwatered when I planted so the first set of leaves started to die, not sure if it's related but last few days these small brown rust like spots have appeared on the next set of leaves. Not sure if it's a deficiency, I am planning to topdress within a week or so.

Any thoughts?

Look at label - it is actually pretty light in NPK.

Needs food - looking pale.

Looks like coco to me.
Maybe ask mr. canuck.

Bag says 1-0-0 … so there’s that.