Massive ping issues since 1.3.2

Hey,

Since 1.3.2, all servers on :25565 show huge pings. This hasn't got anything to do with my connection, as all servers on different ports have a perfect ping, and I've got a good connection anyway.
This was listed on the Minecraft Wiki under Annoyances, but has never been fixed : http://puu.sh/1lwUT
It's not that big of a problem, but it is pretty annoying...

Examples here :
http://puu.sh/1lwU8 - Server on :666, normal ping
http://puu.sh/1lwUd - Server on :25565, massive pign

And the server itself isn't lagging/overloaded, it's got 20TPS, running with 6Go of Ram on a Xeon CPU, so the server itself isn't a problem.
This happens with Vanilla/Bukkit.

Someone said it had something to do with scanning for local worlds on LAN, causing the problem, is this the case ?

Mark