https://userapps.support.sap.com/sap/support/knowledge/en/3628019
3628019 - LIPS-SPE_GEN_ELIKZ cannot be set for non-EWM relevant items | SAP Knowledge Base Article
After completing an EWM delivery, non-EWM relevant items in the ERP return delivery or inbound delivery are not set to completed(LIPS-SPE_GEN_ELIKZ is not set).