For all movement types (e.g. 101), for which label printing is desired, you must maintain movement-type-dependent field selection.
You will find this Customizing under:
Materials Management –> Inventory Management and Physical Inventory –> Settings for Enjoy Transactions –> Settings for Goods Movements (MIGO) –> Field Selection per Movement Type
Include the field WEANZ as an optional or mandatory entry field for the desired movement types. You can add with New Entries