EAN/packaging data copied from reference although base unit changed

What causes this issue?

SInce you are creating the material master record with a reference, the
base unit with the appropriate EAN/packaging data was taken from
the reference record. You then changed the base unit in the current
material master record.

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?

Check to see whether the EAN/packaging data applies to the current base
unit of measure. If not, correct the data.

Error message extract from SAP system. Copyright SAP SE.