Hello,
I've noticed it on the web client, and not yet sure whether it's specific to cards against humanity or if it's more broad, but here's one of the messages I got:

TheObserver has just created a new table of Cards against humanity.

TheObserver has joined at a table of Cards against humanity.

THe correct behavior, which I think was what happened before, is that only the first message would be mentioned.

Unless the observer has created then got invited to another table.

No, I believe this works so that the first table creation message is sent while the master is still viewing the disclaimer, and then the joining message happens after the disclaimer is accepted. I mostly don't have any interest in the global messages channel though, so I could be rong, but I've definitely noticed this one.