I recently asked this question to fella who works in the University of Kentucky apple orchard research facility. He forwarded the question to a geneticist.
Answer > While not impossible, there is near zero possibility a triploid tree can produce a diploid sport.
Triploid trees have near zero chance of producing viable seeds. The Winesap has produced numerous offspring despite the fact the pollen is sterile. That is precisely the reason why Jason Bowen was correct when he stated both the Ark Black and Winesap are not true triploids. Both have produced offspring. The Black Twig, Stayman, and so many other triploids have not. AI is confused because the sources are confused.