I don't know if this individual case is real or not , but I know it can be done , years ago I made a cross between a phrag mother plant w/ the pollen from a paph (don't remember exactly any more , I believe the mother is a hybrid , could be a Don Wimber with a parvi or a cochlopetalum pollen.
I am very sure because the first thing I did was taking the pollen from the mother phrag away to use on a different paph , so the only pollen on the phrag mother is the pollen from the paph.
The flasker took a sample of the seeds & examined under microscope and reported that the chance is almost none since they don't look like with embryo .
However we proceed with flasking , and it did result with one very strong single seedling with multiple grow in flask , the leaves look more like phrag than paph but not quite like the leaves of the mother plant .
Unfortunately , I am not skillfull with raising seedling from flask , and the plant died .
I wish I know a grower who could raise that plant properly at the time i would have donated that plant so it would survive.
The only reason that I had try it, was that I did not have a lot of experience with orchids at that time, so I did not have the inhibition of what can be done/not done nor of trying something not in line with conventional wisdom .
I would say that everyone should do it, if he/she has a lot of paph and phrag flower at the same time.
-Because other peoples say it is impossible does not mean it is impossible .
-Because someone had failed does not mean that you would fail .
-Because you failed before does not means you will fail in the future .