Numerous threads have appeared since the Shadowkey sale update just before Halloween complaining about lag, freezes, game skipping, or running slow, often people report their entire party been affected by lag. These issues are happening regardless of connection, hardware, or number of players playing, I think something about the game itself is causing these issues and hope to say it fixed in the near future.
I personally saw my connection bars which up until the update had always been at 3 bars drop down to 2 right after I downloaded the patch (I was playing immediately before and after the update) and it hasn't gone back up since and I'm still having lag issues.