Why do apps open without I clicking on the notification

[AC Question]

When a notigication comes pops up and goes back to the notification drawer. That is normal. But a few seconds later the app launches itself. For example, a whatsapp notification comes and I don't click on it. Then whatsapp suddenly launches itself.
My phone: Samsung Galaxy Note 5
Android 6.0.1

 

[B. Diddy]

Welcome to Android Central! This happens for all apps, or only certain ones?

 

[Mehmet Efe Karadeniz]

It happens on most of the apps. I experienced it with Google, WhatsApp and Snapchat.

 

[B. Diddy]

Try wiping the cache partition: https://support.t-mobile.com/docs/DOC-27659