The Test Server is up with a fix for the 'non appearing message' issue.

It's interesting. This is actually a very old issue and could happen if the message would fill up with more than 10 messages in 3 seconds. This doesn't usually happen, but it can happen often when you create a new character (as the new character receives a lot of messages for learned schemes when entering the world).

I think that's all to fix with this current optimization build. I'll leave this thread open though in case more issues are found.