Missed call badge icon won’t go away! Why?

When I have a missed call the little red #1 pops up on the phone icon. After I look at it, it stays. I open the missed call info, look at all missed calls and it remains! Deleting the missed call does not always make it go away. It doesn’t happen all the time, which confuses me.

I've have cleared all the call history, there are no voices messages etc. I restarted the phone. The red #1 is still showing on the phone. Can someone please help with this issue? Thank you.