Plant & is the issuing plant

What causes this issue?

For items relevant to plant maintenance, it is possible to maintain an
issuing plant outside the validity area (plant), which is only used in
plant maintenance.

How to fix this error?

Check your entries.
You can delete your entry by entering "!" at the beginning of the field
<ZH>Issuing plant</>.

Error message extract from SAP system. Copyright SAP SE.