In actual costing sales order pick transaction is changing the cost of the item

Hello

We are working on actual costing method.

And noticed that sales order pick transactions are also changing the item unit cost

Like earlier at 3.21 PM WIP product completion cost was 0.01762

but after sale order pick at 5.49PM cost changed to 0.03066

Can someone help on understanding why in actual costing a pick transaction would change item unit cost

Thanks

Neetu