Floris Huizinga

Confirmed for 1.7.2.

Swinging to the south works fine. Swinging towards the north breaks as displayed on the screenshots.

This also happens when you are listening to a music disc using a jukebox. Normal background music starts playing while a music disc is already playing.
(Environment: Windows 7)

I am running a server for about a max of 30 players with 2GB of RAM. The server is running on an 'Amplified' world generation. Even with 15 active players online we are having no issues. The problem is most likely not caused by Minecraft but by the machine running the server (or it's internet connection).

Here you see other text behave the exact same way. (Not a bug)

I believe that this was done intentionally. The spacing allows players to see the difference between a new sentence or continuation of the previous line.

This was already in the game (in previous Minecraft versions). The /tellraw command uses the same way to handle text as previous versions.