They are real opportunists. Take whatever they can get, as long as there is something to eat. I can believe that babies may be kept warm during winter. Early born babies under natural conditions often may be active for several months. And I can believe that they appear as long as there is a little warmth.
Small bodies warm up in a very short time.
It is typical for P. solare , too. Young have been seen in almost every month of the year, as you also wrote. But we do not know what happened with the baby which grew on so fast. If it became only two years old, this is not a good result. Why did he not try to breed the lizards.