Won't ping servers that are outdated, but still online

When you go to your server list the servers that are not on the current version of minecraft do not ping properly, and it says can't connect to server
but they are perfectly fine when pinged on 1.6-.

What I expected to happen was...:
The server should have 1.6.4 in red when it was outdated

What actually happened was...:
the only servers that connected were the ones that are 1.7, and when you ping outdated versions it says can't connect to server.
when connecting to server, instead of saying client oudated, it says
java.io.IOException: Connection reset by peer

Steps to Reproduce:
Find an outdated server thats running and pings OK on the oudated version
then upgrade to 1.7 and ping
it should not work and should not connect