Remove the item line in the make a copy scenario.

var itemSublist = currentRecord.getSublist({ sublistId: 'item' }); 
          log.debug("itemSublist",itemSublist);
          let itemCount = currentRecord.getLineCount({ sublistId: "item" });
          log.error("itemCount", itemCount);
    
          for(i=itemCount-1;i>=0;i--){
          currentRecord.removeLine({
         sublistId: 'item',
         line: i,
          ignoreRecalc: true
        });
          }