My message icon will not disappear on my status bar when I view it through my default text msg app

[AC Question]

Whenever I get a text message and view it and/or respond to it, my message icon and preview will not disappear from my drop down bar/status bar. I could have a 10 minute text conversation with anyone and all of their messages will stay in the drop down bar/status bar as if they haven't been opened/viewed. I am unsure of what to do and I have already tried to get help from Samsung. They advised me to clear my messaging cache the first time, then proceeded to tell me to put my phone into safe mode to see if a third party app is the problem. I can't seem to diagnose it and get rid of the issue. Has anyone had this problem and does anyone know how to fix it? Would be greatly appreciated!

 

[kaaytee3]

This is my question and for anyone helping, I have the Samsung Galaxy s6 edge