SAP Message AJ688 - End of the last simulation period is not clear

Diagnosis
In the last billing period, you executed different simulations up to thedue date using thevariant QUANTI26. In the current period, youtried to start the simulation on this date +1 day. However, the systemcould not determine a uniform start date. The simulations in the lastperiod went until &v1& and &v2&.
INCLUDE ISU_VERARB OBJECT DOKU ID TX

Procedure
Analyze the billing document with the number &v3& in the previousperiod.
Change the schema structure.
Reverse the document.