Dishon or Dishan

I was frustrated by research of the genealogy given in parshas Vayishlach for Seir Hachori. It lists the sons and grandsons in order from 36:20, but it seems that 36:26 is a mistake in the "maleh v'chasar". There are two sons with similar names Dishon (spelled chasar or maleh vav) and Dishan (spelled maleh yud, chasar vav). Both v 26 and v 28 mention Dishan's sons, giving a different list. According to the order of the verses in context, it is clear and obvious that v 26 should list "Dishon" and not "Dishan". In one of the verses it has the name Dishon by the punctuation "Etnachta", so that cannot serve as an answer.

The parallel genealogy in Divrei HaYamim has it as Dishon, as we would expect. One later mefaresh indicates that Dishan died, and in his honor, Dishon changed his name to Dishan. (This is a bit like marking the bottom of box "TOP" to avoid confusion, but they are not responsible to make our learning easier, I suppose. This answer gets an "A" for creativity.)

The best answer I have is that the Masoretic text has a scribal error here of the type conceded by the Gemorrah, and the traditional voweling followed the errant spelling. However, if we ask a ba'al koreh, he will probably tell us that he reads it "Dishan" anyway.