Cannot transact Pick Wave move order. Requested quantity becomes zero when allocate button is clicke

Step 1: Order line is entered

Step 2: Order line is released

Step 3: Transact Move Order form > Allocate     (Requested Qty becomes ZERO when button as clicked. shown below)

Step 4: View Update Allocations > Transact Move Order      (Error message received below)

The move order line remains in Pending Transactions

This problem is occurring for some orders.

What are possible causes and solutions