Why do these records of non-Amazon books have ASINs?

[ValeReads]

There is one Kindle version of this title (ASIN B0DT4WY8S2)—no problem with that. But for some reason there are two ebook versions listed on Goodreads, both of which have ASIN numbers associated with them (B0F27DGBR5 and B0DVFDRWZ6), but neither of which has been published on Amazon. The author sells the files on his website in epub and pdf, but not with ISBNs or ASINs assigned. Just to be sure, I searched for both numbers on Amazon, and the book doesn't come up. So I'm puzzled as to where are those numbers coming from. Also, since there's no distinction between epub and pdf in the format list, should those two records just be combined as "ebook"? Thanks!

[Martin]

Goodreads is owned by Amazon, they add ASINs to everything.
If you want to distinguish between different formats you could ask for information to be added to description, but will need to provide sources to show which is which. Or, do they use different cover images?