The best way to explain this is to show you:
As you can see, the logo is not right. Also, the font is orange, and all the logos on the chat rooms are one of Stack Overflow.
The difference is that below "Rooms", the SE chat says it is about the SE network, while in the SO chat, it states events coming soon about programming.
I do not remember the SE chat page being like that, so something must have happened, unless I am wrong.