Before bug 35026 the MarcFieldsToOrder system preference would simply take the first value from a field if there were multiple - it now throws an error when trying to pull price from 020$c if there are two isbns. To test: 1 - Find a marc file with 2 isbn fields, each including price 2 - Add to MarcFieldsToOrder: price: 020$c 3 - Stage file 4 - Add to basket from staged file 5 - Error: Invalid number of fields detected on field 020, please check this file at /kohadevbox/koha/Koha/MarcOrder.pm line 156