A skipped distribution is often associated with the following message:
Failed to create package: Preferences results in no Ids, Ids can't be blank
Quick Recommendation: Create the distribution by setting "Select Assets By" to "Product ID".
Details: The Channel Rule is expecting a specific format. The list of ISBNs do not correspond to said format. Selecting by “Product ID” avoids the problem since it encompasses all product formats of a given product. The Channel Rule itself will filter out the inappropriate product formats.