Chat's randomly open depending on the machine i log in to

Depending on the machine i log into (cookie’s?) i see old chats pop-up, which i closed before.
Expected behavior is once i close a chat on one machine, it will never pop-up on all other machines, independent on cookies.

We have several bugs turned in on the bug tracking system for this issue. Here is an example:

Just to let you know we are aware of the issue. :smile:

I assume this is about personal messages, not chat, right?

I believe it is for PMs.