Note: While there are other bugs like this one logged none have been "assigned"
Basically any time you get close to another player (within the 1km net bubble) or user objects (bases, fences, crates, hidden stashes, etc) you get a lag spike.
This is bad as it becomes a tell-tale sign that either another player is nearby or user objects are (i.e. objects not placed on the vanilla map). Players use this meta to ambush other players which ruins the game. Same for user objects as many apparently use this to raid bases by just running around the map looking for lag spikes.
Could an async-load of data or merging of network bubbles not be done to avoid these spikes (i.e. to feather in data (crates etc) and players so to speak). It might mean they "pop-in" under some circumstances but I'd rather that than the current lag spikes that given things away. I'll log a separate bug.