R12.1.3 Purchasing: Tax does not default on PO lines

Did you know that there are problems on R12.1.3 with the Purchasing module where information is being lost behind the scenes after hitting the save button?  The MOS document "19176183 Type_1099 Tax Is Not Defaulting To PO Line" from article ID 1991078.1 shows how to replicate this and also what patch is required to fix it too!