Isn't your location repeatedly being sent to the server? It should correct your location a microsecond after walking off to avoid this happening.
I play on servers located on the other side of the planet and I have never had that happen.
Sort of? You can't send position updates every microsecond because the bandwidth would be off the charts, and you'd have to drop most of the information anyway from being out of date. The client uses
dead reckoning in every non-lockstep game to do position updates.
The reason you can usually use ledges to desync in most games is because if you slide off the ledge on the server, but don't on your client, both versions of you are in a valid state because the client and server both made separate valid assumptions on your movement. This is the only way to get lots of people in a game to network with each other, and 99% of the time the assumptions sort of average out into a believable simulation that you are all playing at the same time.
In this case, the networking assumed both were right, but the server has authority, and when you passed through the kill barrier on the dedi, your client recieved the "kill the player biped" message and just killed op_ivy instantly without bothering to figure out where exactly ivy died, because that information is less important than the alive state of the player. The server was trying to assume that since ivy was laggy, they wanted to keep moving between the client messages it saw, so ivy moved a little bit longer until the host saw that ivy had indicated they wanted to move into another direction.
This is also why in really laggy games you'd often see people just randomly die because your client is finally seeing the kill-that-biped message. Only the host has the 'authority' to kill a player. This is why you could standby in Halo 2 for example and jump off a map into the death barrier of any MP map and live until you reconnected.
Fun fact: this is the actual reason I've always favored full autos in any online shooter, hence my love of the AR. Because autos are almost always dead reckoned to keep shooting by default until the player client sends a "i stopped shooting" message because of the amount of bullet events they generate, while single-shot weapons tend to be the other way around, where they only shoot when the host sees "plz make me shoot" message. This is why in standby, you'd see people keep shooting their SMG/AR and then go 'clickclickclickclickclick' because the dead reckoning is telling your box to keep firing their gun in your local simulation. I used to tell my teammates in Halo to switch to the SMG when a standbyer was coming into the base and to fire towards the arm spot, and we would sometimes come back out of bluescreen and the bomb was sitting next to the dead body of the host. Networking weapon meta, y'all.
edit: this was also why when you stop firing the AR or SMG in Halo, sometimes it would spend like 1 or 2 more bullets after you stopped firing, because on the host you did fire off a couple more rounds. Bullet refunding is the opposite problem, you fired on the client but the host never saw it so your client gets the update of your ammo count and puts bullets back on the HUD.
tl;dr multiplayer on the internet is basically one giant magic lie that happens in real time and it's fucking amazing it works in the first place. Artifacts like these occur because in this house we obey the laws of physics.
