I can confirm this. Also, the surround-sound synchronizing is a bit odd. I'm running Minecraft on OS X 10.8.4 using Apple's Java 1.7[.]
Is the server port-forwarded or does it use VPN software like Hamachi? It seems like it is an issue with your router, not Minecraft. When was the last time you restarted your router?
Can confirm on 13w24a.
I can confirm this. Also, the surround-sound synchronizing is a bit odd. I'm running Minecraft on OS X 10.8.4 using Apple's Java 1.7[.]