What is going on with the mission:
When player selects "Start test" they send 500 public variable arrays with random values (array of 3 numbers) with each next array having 1 more value than previous one. (init_ns.sqf)
This test does not reproduces the situation happening on live servers, it forces one of clients to send extreme amounts of public variables over network which creates lag very similar to that happening on live server, actual mission (King of the Hill) doesn't send this amount of public variable data.
Additionally repro seem to work ONLY the first time you run the mission after starting the server. With all next mission starts server recieves (client sends?) public variables MUCH quicker resulting in less lag and desync numbers on JIP player. If test fails or you need to run it again MAKE SURE to go back to servers list and create server again.
This repro wasn't tested on dedicated server but I assume result should be similar.