Anytime you get within network range of a decent amount of items (in storage or on players) it will flood your client and cause lag. This is especially worse now after the new vehicle simulation changes, one second you're driving on the road, next you're in the ditch, all because you loaded in a base or player.
Video reproducing the issue with an item counter on display (tlc count)
https://streamable.com/wvusx6
I can imagine there's more things that can cause this like just loading in a town for example. This is the most irritating and frustrating thing to deal with in this game as it can cause massive issues like making cars borderline unusable, and ruining encounters with enemies
Here's a prime example: https://streamable.com/re7672
(I ended up reducing the storage network bubble to minimize the effect on players away from bases)