Hum, with my humble process and physics knowledge, I can think somethink like that:
Whatever the process is, if there is heat involved, a difference of temperature causes deformations, and most of the time, it's due to a difference of thermal inertia, which is linked to the difference of mass of material of the piece.
Typically, the print of a large plan surface causes warping at the edges because the center have still some heat gathered, while the edges are cooling easily. The warping happens in the cool direction: when you cool something, it generally retracts. If you have piece of material, the cooled part will retract while the still hot one will stay larger.