When a FOLIO library supplies a title, the response to ZFL contains the following: 

...<ill:deliveryInfo>      

<ill:dateSent>2025-04-01T11:06:01.524145374Z</ill:dateSent>      

<ill:itemId>040007908554,PM 734,040007908554</ill:itemId>      

<ill:sentToPatron>false</ill:sentToPatron>      

<ill:loanCondition></ill:loanCondition>      

<ill:deliveredFormat></ill:deliveredFormat>    

</ill:deliveryInfo>

Thus, the content of itemID (marked red) is transmitted as call number to the requesting library. For non-FOLIO ILS (Alma, Sisis, etc.) the whole string is then displayed in that system accordingly (marked red).

The field itemID should only contain the call number (i.e. the effective call number) and no further information.

The effective call number should look like this: {{item.callNumberPrefix}} {{item.callNumber}} {{item.callNumberSuffix}} 

It is not necessary to transmit the item barcode (and definitely not twice) and it causes problems for non-FOLIOs.