Leapp upgrade not updating system to rhel 8

I am trying to update system from RHEL 7 to 8
leapp preupgrade completed successfully and leapp upgrade also completed successfully no errors found all is green.
But after completion of leapp upgrade i rebooted the system, generally it take 20-30 min and os gets updated to rhel 8 but server rebooted in 5 min and still OS is rhel 7.9