When call is going on in the phone and we press the home button a calling widget came. When we drag that widget to the down we'll see 2 options - hide call - end call. So when are dragging that icon and someone suddenly end the call the option will remain on the screen permanently. We have to restart the phone inorder to remove that options. I'll share the screenshot with you.
Link : https://imgur.com/a/Rn8fZxN
Kindly please resolve this issue.