& is not a valid field for T242B according the field catalog

What causes this issue?

The characteristic values are not stored in T242B and therefore cannot
be maintained there.

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?

Please look at your aspect to see which check table is entered for the
field.

Error message extract from SAP system. Copyright SAP SE.