Receipt quantities are cascading across Blanket Release shipment lines

 We are creating a blanket release with multiple shipments for delivery the same day. Each load is recorded in a custom form that also interfaces data to another system and submits the data to the receiving interface. We have recently upgraded to 11.5.10.2 and since the upgrade any over-receipts are allocating across the shipments (as per cascade receipts although the cascade receipts flag is not set). For example Shipments 1 and 2 are both for 30MT. The delivery is 31MT which is allocated 30MT to shipment 1 and 1MT to shipment 2. If the next delivery is 31MT we end up with 32MT against shipment 2.