Well, I'm working on an adventure map. When I tested a command block with a command "/tell @p..." the word that was on the edge of the chat was cut in half, half stayed on the line up and the other half on the bottom line.
I noticed that the nicks of players - in this case, my nick is JohnKCraft - are also divided and lose the "Formatting codes".
The two commands were:

tell @p @p test TEST test TEST test @p TEST test

tell @p @p test TEST test TEST test TEST test TEST test

And I received, respectively, as follows:

@ whispers to you: JohnKCraft test TEST test TEST test JohnK
Craft TEST test

@ whispers to you: JohnKCraft test TEST test TEST test TEST t
est TEST test

Attached images...

Edit:

(I removed what I said here about the symbol §). I made a post in the forum about it: http://bit.ly/1ccs9N8. Check it there.