its a peloric paph. some do breed odd paphs. Orchid Zone used to have a collection of double and triple pouched paphs. Strangely odd indeed to come from a seed.
It could also be caused by a Colchicine Treatment. Colchicine is a chemical that is often used to induce polyploidy in plants. Basically, the colchicine prevents the microtubule formation during cell division, thus the chromosomes do not pull apart like they normally do. Because chromosomes function as the blueprint directing all cellular functions, they cause twice as much size, twice as much petal thickness or twice as much petal in your case. In most instances, the net effect on the plant grows slower Because there is twice as much genetic material to copy each time a cell divides, growth takes longer. Leaves tend to be broader and thicker.
Polyploids cannot breed fertile offspring with normal diploid plants and i bet that plant is sterile. Enjoy it