Logically the system should not allow a change in quantity when you move stuff between locations , or warehouses or sites, what you out into the transit location should equal what comes out.
When you receive against a Purchase order its coming form outside so you are not in control so the amount received could be over or under, There is an AP liability cheated for the excess. If you were to over receive with a transfer order- then the in transit warehouse would have negative stock.
If there is less stock then it can be written off as scrap. If there is more stock then logically it must have existed and the theoretically correct process sis to adjust the stock in the transferring from warehouse and then amend the transfer order.
When the stock is adjusted or written off there is a financial value change to the company's balance sheet. and ou can't just invent more value without a reason.
We live in the real world and theory does no so easily fir your situation. You also have consider the case that the person transferring made a genuine mistake e.g. miscounted or wrongly typed, or that the on hand stock was wrong or a gauge gave faulty reading etc. So now the question is who should make the correction. Ideally correction should go back to the source. - but it also needs to timely. You need to book in the right quantity or the error is perpetuated, If you are int the same company then it may not matter financially which warehouse does what adjustments. .
Its important to have a process everyone agrees ad that is consistent for all incidents, The person receiving will not know the reason for the discrepancy but is responsible to receive the correct quantity. I suggest
Complete he order for the delivered quantity
Do an inventory adjustment for the difference ( effectively a mini stock check.).
Create a daily log template for such adjustments-order number, item, amount to adjust, name of person, reason code/comment.
Let a manager or QA review and sign off daily and then file for audit purposes (auditors tend to be funny about multiple stock adjustments unless documented).
Adjust receipt by receipt or at end of day or even a summary adjustment weekly.
Send a copy to the transferring warehouse either to the warehouse manager or finance to assess whether any further adjustment is needed to inventory in that warehouse.
P..S. for the site invigilators - this site is dreadfully slow and it takes ages to reply