If you are desynced, your local diablo doesn't show you what the server descided is actually happening. So a player could seem to be on the other side of your screen while he's actually right in front of you. The server is the highest authority.
I vaguely recall this being part of a hack-pack. Though I have not bothered to install third party, I speculate you could specify one target for all your skills, allowing for instance your ranged attacks to allways target the 'right' target. Bonespirits and Guided arrows for instance have a mind of their own. They will attack the closest thing to where you targeted them. This could very well be a minion of your opponent, while by targeting your actual opponent, you would end the duel quicker. I can't say I like this method, since it is beyond lame and it would take a very weak dueler to have to employ such methods.
Mind you, this is what I think it is, there could very well be some legitimate method that bares the same name.
- charge lock
Could be you clicking on a person and holding your attack button pressed until the said person is dead.
Or, when you charge and you get 'stuck' in your charge, unable to do anything else. Exit and rejoin being the only option.
Or, when you charge and while in your charge, your holy shield 'runs out' you get a bit stuck. weaponswitch or take off your weapon/shield to 'unlock' yourself in this case.
No idea, I'm glad we don't have mixed classes like that in classic.