That is not an issue, but good to know — I can use it to make my jumps a bit smoother 
The issue is when they leave chat and forum by closing window/tab/browser or using (back to) Forum, and later opens chat again they are finding thmeselves browsing list of private chats insteaf of latest used chat channel or first one with unread messages.
And I would bet that most of forums in the world aren’t using so many channels that showing any kind chatlist would be beneficial. Including B2B-side where 1:1 chats can be more common than free-for-all bubbling channels, but even then should put a customer/user directly to channel (unless there is need to ask from customer what kind chat help he/she/it needs, that’s one scenario in deed).
Another default setting to adjust? There is quite many already, though.