If Replication rule with specified schedule is disabled/enabled via context menu it may cause scheduled task to disappear from Windows Scheduled Tasks and never execute on time
ITMS 8.7.x
Enabling policy via content menu does enable the rule, but does not reactivate schedule, because policy can be on without defined schedule.
Change schedule in the console, enable and Save policy in the console in right pane and not via context menu.
This logic is changed in ITMS version 8.8 and above