1 seed, 2 seedlings? Help!

So, recently Ohio legalized and I wanted to dabble in growing. This is my first attempt. Grand daddy purple auto. I got 3 of them in 3 separate 3.5g pots. Happy frog soil and just water so far. I planted 1 seed in each pot and they all sprouted. Today is the 8th day, went to go check oh them and noticed a 2nd seedling sprouted. How did this happen? Is it a weed or something that needs to be removed? Should I keep it as is? Any help would be appreciated. I've attached a photo of the pot in question. You can see the little guy on the bottom right.

edit - the white stuff on top of the soil is diatomaceous earth.

Right now I’m not 100% sure, but I think it’s an undesirable weed (not cannabis). Let it go another couple days to see what the first true leaves look like, if it’s not cannabis, just pull it out.

Not cannabis.