Reference field formula
I can't figure out how to copy a formula we use for a reference number into a different custom field. When I copy and update the custom names it tells me that "Packaging Request Type is not a valid field in your system". I'm not sure what that means? It's a custom field we have been using and looks the same as Tactic Type from the current formula.
Current formula:
CONCAT(LEFT({DE:Packing Request Type},2),"_",IF(MONTH({DE:Final Files Due to SUPPLIER})>=8,RIGHT(YEAR({DE:Final Files Due to SUPPLIER}),2)+1,RIGHT(YEAR({DE:Final Files Due to SUPPLIER}),2)),"_",{referenceNumber})