Order &1 with lot size &2 &3 will not be backflushed

What causes this issue?

An order with a lot size not equal to one was to be backflushed in
Model Mix Planning. This caused an exception situation because Model
Mix Planning usually transfers a sequence of isolated orders to the
production installation.
Possible causes:
The model mix plannng run used posts the orders cumulatively and not on
an isolated basis (see also: <DS:DE./SAPAPO/SEQ_PLANNING_BASIS>Planing
basis of process</>).
The model mix planning run has not been executed for a long time.

System Response

Backflushing does not take place.

How to fix this error?

In order to isolate the order, proceed as follows:
In the initial screen for sequencing, enter a horizon in which the
order lies.
In Sequenzing, execute takt-based scheduling by selecting
<LS>Takt-based scheduling</>.
Das System deletes the order and creates n orders with the order
quantity 1.
You can also reschedule the order into the future using the expert
function and process it in a a model mix planning run which posts
orders on an isolated basis.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.