Quantity delivered by shipping differs from GR quantity

What causes this issue?

You have attempted to delete an item of a
<DS:GLOS.3526C047AFAB52B9E10000009B38F974>stock transport order</> for
which not all goods have yet been received.

System Response

The item cannot be deleted because the quantity delivered by the
supplying plant does not agree with the GR quantity posted in the
ordering plant.

How to fix this error?

You cannot delete the item until the full quantity of goods has been
received.
You may be able to delete the delivery in the supplying plant (or
arrange to have it deleted).

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.