Matl &1, batch &2: Receipt posting to single-unit batch with stock &3 &4

What causes this issue?

Batch &V2& of material &V1& is a single-unit batch. Stock already
exists for this batch: &V3& &V4&
This can happen for the following reasons:
The batch has already been posted
You have already entered a receipt for this batch in another item of
this document.

System Response

The item cannot be posted.

How to fix this error?

INCLUDE NA_EINGABE_PRUEFEN

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.