Why does my scheduled report return different numbers than if I run the same report run manually?

Summary:

We have a report contains large number of data and the problem is while running the report manulally by "queuing " the report and scheduling the report gives different set of results even tried to by changing data sources from report database to operational database and filters are same while scheduling and manual execution of report

strangly while executing same reports with one month back dates as filters results are matching

main filters applied here are incidents.update graterthen and incident.updated lessthen specific ramge

any suggestion are accepted

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