WhatsApp started showing Facebook colours
WhatsApp has a feature to mute chats so you don't get updates all the time for group chats you only want to visit that often.
In the last few weeks I have noticed that if I am using my phone a WhatsApp notification shows up in the status bar which says - "Checking for updates" but it's only updates in muted chats. However seeing that notification makes you engage with the app. Very annoying and under handed to get more engagement. Stop using it