I'm having exactly the same problem with Yopaz IceStar, I bought it for the PS1 version but now only get downloads for the other versions. I think this is the reason:
"Individually priced files come with a important distinction with regards to ownership: The buyer will only continue to have access to these files if the price they paid satisfies the minimum price you set on the file. This means that if you change the individually priced file to be more expensive you may lock out access to that purchase tier from existing buyers." https://itch.io/docs/creators/pricing
So because OrionSoft happened to sell it a bonus tier above the base purchase we lose access if the price ever increases. Good job, itch.