Sub-item & has too many serial numbers

What causes this issue?

Sub-item quantity &V1& is lower than the number of
<GL:serial_number>serial numbers</>.

System Response

The number of serial numbers in sub-item &V1& is included in the
incompletion log.

How to fix this error?

Please delete the superfluous serial numbers or increase the quantity
accordingly.

Error message extract from SAP system. Copyright SAP SE.