Two shipments created for a Transfer Order

Summary:

Two shipments created for a Transfer Order

Content (please ensure you mask any confidential information):

A expense transfer order ( from Internal Requisition ) is created with 5 lines having same source org, destination location, Requested delivery date, Scheduled ship date, Requester. When 'Schedule Pick Wave' was run, two shipments got created - Shipment 1 was having 3 lines and Shipment 2 was having 2 lines. There was no backorder when pick wave was created using 'Schedule Pick Wave' process. Expectation is to have single shipment for the order. This issue is occurring randomly for the orders.

Pick Release Batch Size is blank in shipping parameter setup.