Cant pick up items that I gave my friend

So I was playing with my friend. I am level 16 or so and he is level 4.

An essence dropped and he wanted me to have it after picking it up. He dropped it and it was greyed out.

To test this I dropped an orb of transmutation, he picked it up, and then dropped it again. Greyed out.

We opened a chest. A armor scrap dropped. He picked it up and dropped it. Greyed out.

We are playing with free-for-all on. Normal items seem to be able to be dropped, but currencies, even the ones that I originally give him, I can't pick back up after he has picked them up.

Not really a big deal, but does anyone know why this is hapenning? Thanks for the help!

You have to have a level 25 character on your account to be able to trade away currency and uniques. This is a measure to make it harder for people doing illegal things to make accounts to pass the items to.