This might fall into the category like the scenes of Joachim and Khan on CetiAlpha ... Scott SAYS they filmed them, but nobody has seen script pages or bts pics of them filming them, so it is kinda hard to call.
Having met Judson Scott, and discussed his "scenes with Khan" long before it was ever (mis)reported in places like "Starlog", I can tell you that the scenes he's referring to were
rehearsal scenes that he and Ricardo Montalban used,
at Montalban's house, as they prepared for their roles over several days.
They weren't filmed, and they may have been impromptu drama exercises, not written scenes. Montalban liked to bond with his co-workers this way, and he was finding it difficult to get himself back into the headspace of Khan from TOS. In their interpretation - and well before they got any directives from higher up - they assumed that Khan and Joachim were actual father and son.
If Scott has since said in print that the scenes were filmed, he may be mis-remembering or has been mis-quoted. Certainly, the original version he told me was that they were rehearsal pieces only.
For the longest time the "Khan's baby" scene was thought to be apochryphal until a still surfaced from it.
Which ties in nicely to the Scott anecdote, because during filming, Scott got to see the (unused) painting of the family portrait - Khan, Marla and toddler - which is how he knew that Joachim wasn't Khan's son after all. Nevertheless, in his convention appearances, if asked by the audience about Khan's relationship to Joachim, Scott will invariably say, "He was my Daddy!"
When I did an interview with Paul Winfield, before ST II's release, he was surprised that the story of the black-faced white stunt man had reached Australia, and he confirmed then that "Terrell" had rolled down a hill because a toddler's face had appeared in a porthole of Khan's planetary abode.
