Why do I get 2 notification icons for facebook messenger? (one black and one white)

[Android Central Question]

Every once in a while I get 2 icons for facebook messenging in the android notification bar. (one with black circle with a white thunder , and the other icon with white circle with black thunder), so it's 2 different looking icons

Not sure if it meant anything. It has been bugging me for a while. Thanks in advance!

 

[abcdeqwer]

These are how both icons look like in my android notification bar for references....

 

[kukuku0511]

You have them but you don't have any secret conversations or what?