Hello,
Are you are using Classic or event - driven, in case if you are using event - driven, check whether you are using fixed kanban quantity.
In this classic KANBAN procedure, the kanban signal always only triggers replenishment for the kanban quantity defined in the control cycle.
Please refer this useful help link,
Classic KANBAN - PP KANBAN - SAP Library
Kanban with Quantity Signal (Tcode PK22) or you can use BAPI_KANBANCC_WITHDRAWQUANTITY
Best Regards,
R.Brahmankar