Please check last sched.date & against breakdown indicator

What causes this issue?

It could be that the last scheduling period does not match the
<DS:DE.BISDAT>"valid-to" date</> and the
<DS:DE.OIA_ENTLU>breakdown indicator</>,
which means that the last period has a date which is too early. A
subsequent scheduling period may have been deleted manually or the
validity period was changed after the quantity schedule was created.


&SYSTEM_RESPONSE& / &SYSTEM_MESSAGE&
This message is controlled by Table T160M (System Messages). If the
type does not have an initial value (empty), it appears as a warning
message.

How to fix this error?

Check the "valid-to" date in the quantity schedule.
Check the breakdown indicator.
Check the schedule lines (last schedule line).
Insert a scheduling period after the last scheduling period.

Error message extract from SAP system. Copyright SAP SE.