Some of you will definitely be aware of the on-going issues with the ASIN bug. This has been an ongoing pain-in-the-as ... issue for several weeks now and BL's IT department has no ETA on it being fixed so here are a few facts here that might help:
1. Some ASINs are being rejected by BL as invalid. They are, in fact, valid and point to legitimate records on Amazon.
2. This error only occurs when you try to edit a kindle edition, or if you're trying to add a new book and the ASIN is deemed to be one of the 'fake-but-not-fake'. This is because these are the only times BL is testing the number against whatever algorithm they use to determine valid ASINs. Automated imports still work.
What does this mean?
If you try to edit a kindle or audible record, you might get an "Enter valid ASIN number" error. There seems to be no pattern to what will get rejected that is discernible to humans who don't eat mathematics for breakfast.
You can still add covers: use the "Add Cover" button under the big green box, not 'edit'. (This doesn't work for changing covers, just adding new ones.)
The workaround: you can search the ASIN number in the search box, and it will import the edition through amazon, bypassing the validity check. The hitch: the record comes through sans cover or much of anything else; covers can be added as mentioned above, but everything else - no dice. So, ymmv.
This is true for librarians too. The only way around it is to email Kate and request that she forces the change through from the backend. She's super-nice about doing it and quick too.
I have to admit though... it's a pain in the butt. Especially if you have 3 or more pages of edit requests to go through. So, and this is me throwing myself under the bus, I've stopped doing it. On records that reject ASINs, I'm taking them out, while making sure the correct ASIN is in the source link field (in the form of the Amazon page for that edition) so the information isn't lost. Alternatively, if I find the corresponding ISBN number, I'll use that (mostly for audiobooks).
If you have a kindle edition that you cannot edit - definitely email Kate (kate@) and she can sort it out from the backend - she might even be faster than us librarians. Alternatively, file a book report, choose "other" and just let the librarian know that the ASIN is one of "those" and let us know what you need updated (with a publisher link if possible). The ASIN might look like it has gone walkabout, but you'll get the rest of the record completed. :)
So if you notice a kindle edition missing its ASIN and you were sure it was there before, that's what's happened and I'm sorry - it was probably me*, and when they get this bug fixed, the ASINs will get added back.
*Dear Kate: please don't kill me. Or de-librarian me.