New leaves growing out from the cotyledons?

[greenpants]

I'm new to indoor growing and autos, is it common for new leaves to grow from the cotyledons?

 

[Carcass]

It happens occasionally-I usually just wipe them off,they don't really grow much if you leave them there.

 

[greenpants]

Cheers, carcass! First time seeing them so I'll prob just leave them be.