Recurring jobs not running in random instances

We have implemented hangfire in our mvc azure web application to schedule some reports. We have total 5 reports for which we used hangfire to schedule their execution. Since last few weeks we have noticed that one of this report suddenly not getting processed when the request is placed.

Code for recurring job is as mentioned below:
RecurringJob.AddOrUpdate(x => x.ProcessWorkerReportRequests(false, 0, reportName), Cron.Daily);

While looking about this issue i found that sometimes web app gets stopped due to inactivity and they suggest that we should keep “Always On” in case of Azure web app. That is set in our case but somehow random jobs for one report only never gets started.

What could be the reason for such behavior?