The batch will be classified automatically

What causes this issue?

You are creating or changing a batch that has not yet been classified.
Since a batch class has already been assigned to the material to which
the batch is assigned or to another batch for the material, this batch
class is also assigned to the current batch automatically.

System Response

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

How to fix this error?

Error message extract from SAP system. Copyright SAP SE.