Stunted?

Looks fine - not stunted. Probably the large pot, tiny plant context is slowing it down... It's probably focusing on roots trying to find limits of the substrate volume. Once it kicks into gear it probably won't be too far behind if you compare at 4-5 weeks out to a plant that was potted up properly, but you also have the pains of watering a tiny plant in a large pot and the elevated risks that brings to the equation for no reason. Always better to use size-appropriate pots and pot-up as needed. This should never shock a plant unless someone pulls out the GI Joe Kung Fu Grip (tm) on the rootball. Don't ask a toddler or someone off the short-bus to do it and you'll be fine.