Document also contains tax code &

What causes this issue?

You have specified particular tax codes in the customer or vendor
items. However, other codes also occur in the G/L account or asset
offsetting entries such as &V1&.
Consequences:
These G/L account or asset items are not taken into consideration when
determining the cash discount base amounts.
If a payment is made with cash discount, these tax codes are not taken
into consideration in the case of a possible tax adjustment.

How to fix this error?

Check whether the codes have been set correctly in the customer or
vendor items and replace them with "**" if necessary.
INCLUDE 'CUSTOMIZED_MESSAGE_INFO' OBJECT DOKU ID TX

Error message extract from SAP system. Copyright SAP SE.