The server has been getting DDOS'd recently. That is probably the cause. Once the losers from another UO shard are tired with the bullshit script kiddie games things will go back to normal. Until then I'm not sure I would risk too much in PvP.
I've experienced this months ago outside of any mentioned DDOS. It seems to be a known issue that's only resolved by constantly having to re-sync the client using the Razor hotkey or opening paperdoll once you notice it. Not sure, but I believe it happens when you try running while lagged or casting. Like when you see the rubberbanding effect from trying to run while casting. Seems like it happens more when there are larger groups of people on screen. This was the only issue I had in PvPing and to me it's ruins the game as it becomes problematic to remember to resync constantly while being chased by warriors.
Sounds like your connection had dropped packets or weird packet latencies. Have you tried running UOTrace to see what your connection is like while playing? One thing that may sound counter intuitive is to get a VPN client and connect to a location on the west coast and see if your reliability is better. I've seen it improve connections and ping times enough to smooth things out.
