Sorry about that…my mistake. Thanks for posting this here, though.
Yes, because we don’t show the chat header icon when you are in chat on mobile, we are using this area to indicate that there are new chat notifications while you are in chat.
But I see what you mean — it is confusing to show a notification for the channel you’re in, when you’re scrolled up in the conversation. At least, it’s confusing to show it in that area. I could see wanting to do something to the 
icon in the channel to make you aware of new activity in your current channel, but let me ping @chapoi to see what she thinks.