Thanks, everyone for your input. We were able to figure it out. Here is the resolution:

I had made an assumption (silly of me, I know!) that since the schedule is for 24 hrs, it means that it will run continuously starting from the time set.

What I mean by that, we had set it to start at 7 pm. I expected it to run every hour till 6 pm the next day. A new cycle would then starts at 7 pm.

That assumption was incorrect. It actually runs on a 12 hour day. With the new cycle starting at 12 am. So, since I had set it to start at 7 pm, it ran only 5 times before shutting off.

We set it now to start at 12 am and that would run the whole day. Problem solved!