Why do some texts disappear shortly after being sent or delivered?

Sometimes when a text arrives, I open the cover of my samsung case for my note 4 and it disappears...other times it does not. The same can happen when I send a text...most go and others disappear. I have friends who have experienced the same problems with their samsung phones

Welcome to Android Central! So you see the text notification, go to your Messaging app, and find the text isn't there?