I was PVPing with a friend, but they couldn't deal any damage to me. It must of lasted about 5/10 minutes then fixed itself, without re-logging. I think we just assumed it was a loss-spike of somekind.
There is a thread somewhere by cannon, about checking your connection to the server or something, might be worth a look.
EDIT: might be worth adding " -lag" (without the speech marks) to you FL shortcut too