1.5.2 clients show server 1.6.1 as 1.3 in Multiplayer screen

When viewing a 1.6.1 server in the Multiplayer menu on 1.5.2 it shows as 1.3. This has confused a few players of my server and I'm pretty sure its a glitch.

Screenshot: http://puu.sh/3qpkc.jpg
Definitely a 1.6.1 server: http://puu.sh/3qpn7.png