Grace period before people loot your spoils

Every character has a gigantic invisible box around them ...

The loot block timer on dropped items starts when your client acknowledges that they exist. That is, if a monster drops some mesos and you're WAY off screen when it happens, and you later go over a minute later to pick it up, you won't be able to pick up anything until 10 seconds after the item is in your box.

...

As for being loot blocked from your own items, I'd assume it's just lag.

Thank you for putting that into writing; I had been aware of it but hadn't quite thought of it in that way.

I will have to try to notice whether the pickup problem applies more often to items that drop off-screen. I don't think it's lag, however, unless it's very random. For example:

I kill a nest golem that I'm standing right beside (as in, I'll take touch damage if I move over a few pixels), it drops a "destroyed nest" and some mesos, my pet walks over and picks them up. Now I kill a jr newtie on the other side of me, yet when I walk over to pick up the stuff it just dropped, neither I nor my pet can get the items immediately.

I also noticed this when I was killing slimes and stumps for that Easter quest. This resulted in a large scattering of items due to me using Ice Strike. Some could be picked up immediately and others could not. I wonder if there's some sort of random delay created by the server.

This used to be worse a long time ago. If I had two pets out, and the pet without the meso magnet & item pouch equipped walked past any items, I would not be able to pick them up for several seconds, whereas if the lead pet passed them, they'd be picked up. Apparently some patch changed this behavior.