When a command block is given the /give command with @a as the second parameter and the selected player has died at least once since he connected to the server, the command spawns the item at the servers's spawn instead of at the player's feet.

Steps to reproduce

1. Enter the server
2. Die in some way
3. Trigger the command block with the command /give @a stone (for ex.)
4. Be sad because object hasn't spawned on you

If two players are on the server and one has not died yet, it will spawn the item right at that player's feet, and the other one that died will not receive the items.