Table & does not meet target structure for incremental conversion

What causes this issue?

This table has already been converted incrementally. A further check has
shown that the structure of the table differs from that displayed in the
ABAP Dictionary (SE11). This means that after the incremental conversion
there is an inconsistency between the definition in the ABAP Dictionary
and in the database. This may prevent the system from accessing the
table, causing application programs to terminate.

System Response

The upgrade phase PCON stops.

How to fix this error?

You have two options:
Use the transaction ICNV to reset the incremental conversion. Phase PCON
then adjusts the complete table again in the database. This may take a
long time. To do this, select the table and choose <ZH>Edit</> ->
<ZH>Reset conversion</>.
The definition of the table in the ABAP Dictionary is adjusted to the
existing target structure. This retains the result of the incremental
conversion. In this case, contact SAP Support (component BC-DWB-DIC-AC)
before taking any further action.
Never ignore this problem by continuing with the phase PCON and making
no corrections. Otherwise you will encounter problems in later upgrade
phases and during productive operation.

Error message extract from SAP system. Copyright SAP SE.