No 10-digit ISBN?

[spin52]

I just uploaded a new paperback, using a KDP-issued ISBN, and got the standard 13-digit number. But then, instead of the additional 10-digit ASIN on the Bookshelf, I got a second e-book type ASIN, starting with B0 ..
I went back over my other books, and all of them, including one published only a few months ago, have both a 13-digit ISBN and a 10-digit ASIN, with no letters. The 10-digit number isn't just a truncated version of the 13-digit one, but has different numbers.
So is this something new? And does it matter? It's just that some promo sites ask for a 10-digit ISBN, which I don't seem to have for this book.