Triggering outbound shipment IDoc on change data in SAP

You need to ensure that Output Type has got "Multiple issuing" checkbox ticked in T-code: V/82. This is available in “General data" section of your message type.

It seems to be a configuration issue. You should try checking this:

Go to SPRO → Logistic execution → Transportation → Basic Transportation Functions → Output control → Maintain Output determination for shipments → Maintain Output Determination procedure.

You can refer this SAP Thread for more details:

SAP Thread

Refreshing list viewer data selectively in SAP ABAP