Why does my Samsung S6 keep vibrating for no reason?

[AC Question]

why does my Samsung s6 keep vibrating for no reason

I have noticed a large circle with a small circle in it on the upper left corner near the battery icon

 

[B. Diddy]

Welcome to Android Central! Do you see it when you swipe the notification panel down? If so, long-press it and tap App Info.

 

[anon(749368)]

Re: why does my Samsung s6 keep vibrating for no reason

Maybe it's the app optimization feature. My s6 kept notifying me of something and I couldn't figure it out until today when it happened as I was using it and saw the app optimization pop up as the notification came on....

The panda has spoken