The same EAN can be defined multiple times if need be, with different metadata ( except for the EAN itself of course ). So here is the issue: The basket branch is set to Library A The EAN is set to Library B Koha searches for that EAN with the basket branchcode Koha does not find one Koha then searches for that EAN that has no branchcode set ( e.g. "All libraries" ) Koha finds no matching EAN Koha then puts a cryptic error in the error log that you as a librarian cannot see!