I'll add some things so I can look into it, but it sounds as if you were desynced. The reason why you can still pick them up is because pickups aren't completely controlled server side. Some pickups are completely the same as in the singleplayer, so the game already knows what to do when you pick up these pickups (health, armour, weapon pickups). Even when you completely lose connection to the server, you'll still be able to pick these up, and for example get armour, since it just relies on GTA only. The teleport pickups (green houses) have some code on the server side, since we have to tell it: "if someone picks up this pickup, he should be teleported to location x". That's why if you get desynced, you'll still be able to pick them up, but you won't get teleported (since it doesn't communicate to the server that you picked it up).
