iPhone reminder app not showing reminders

I am using iPhone 6+. Updated to iOS12.1. I am using the Reminders App to keep track of different tasks. Recently, maybe within the past couple of weeks, when I access one of my Lists, even though there is an indication of something being on the List, the list is vacant. And the crazy part, it is not all of my lists, where I am having this problem. Out of 30 lists that I have, I am unable to see what is on 8 of them. And these are the most currently used lists. I have closed the app and restarted. I have powered down my phone and restarted. All to no avail. I have signed into iCloud and there I can see all my Lists and data.

What else can I do?