It will stay at the same position and new messages remain hidden. This seems to be happening to me a lot more now than it used to. I'm not sure what causes it.
After upgrading to the App Store version, I'm getting this, too. This also seems to contribute to all messages going to the console pane, even when that channel is the active one.
It will stay at the same position and new messages remain hidden. This seems to be happening to me a lot more now than it used to. I'm not sure what causes it.