This is perfectly normal and exactly how cannabis seedlings are meant to grow.
The small rounded leaves (cotyledons) are not leaves in the true sense, their only purpose is to protect the growing tip as it pushes through the soil. Once they reach the surface, they peel back to expose the true first leaves, the serrated ones, to the light. Your plant is doing exactly this, which it is supposed to do. It does not have any problems.
Eventually, within 10 days or so, the cotyledons will turn yellow, dry up and then fall off or wither away, and again, this is perfectly normal.
The cotyledons have no role in the growth of the plant and as I have already said, are not leaves in the true sense, but protective covers for the true leaves that shelter within the cotyledons as the sprout pushes up through the soil.
Hope this helps, Organoman.