Supplier-specific data were not saved due to error &2 &3 (see long text!)

What causes this issue?

While saving the supplier-specific data of the business partner the
following error occurred:
<ZH>&V1&</>
<ZH>&V2&</> <ZH>&V3&</>
The business partner was created/changed, the corresponding supplier was
not created/changed.
<ZH>Background</>
In your system, the so-called post processing office (PPO) is active.
The update of the supplier-specific data is delayed (occurs technically
"on commit"), while all non-supplier-specific business partner data are
updated directly after pressing the save button. Due to technical
reasons a "normal" error message is not possible any more during "COMMIT
WORK" processing. Because of this errors that occur during processing of
supplier-specific data are saved in PPO and the corresponding
supplier-specific database tables are not updated. This leads to the
situation that pure supplier-specific fields in transaction BP are empty
after saving, although they had been filled with values before pressing
the save button.

System Response

Certain supplier-specific fields in transaction BP are empty after
saving, although they had been filled with values before.

How to fix this error?

Correct your entries according to the error message mentioned above
(also available in the message short text in brackets) and save the
business partner again. If needed contact your system administrator.

Procedure for System Administrators

You can get further details related to the error directly in PPO. For
accessing PPO start transaction MDS_PPO2 and enter the corresponding
date on which the error occurred in field "Technical Creation Date". The
concerned business partner should then be available in the result list.

Error message extract from SAP system. Copyright SAP SE.