Hi @dr1992
Then change the reference to ‘Quote Number’ so that when you try adding same item it fails and you can catch it by try catch or ignore by using continue on error property.
Alternately when you get the queue item,add a if condition and you can check using get queue items if there is any queue item already processed with same quote number by using property Reference ‘startswith’ by changing reference like this ‘Quote Number - Customer name’ and stop processing the item if found
cheers