Summary:
I was playing as Sniper, got the shit harassed out of me, so I got my team's courier to send me my Salves and Tangoes. Whne the Flying Courier came, I got it to drop my stuff onto the ground because my inventory was full. The items I dropped couldn't be picked up.

Repro Steps:
1. Buy Consumables using Flying Courier.
2. Send the items to you.
3. Drop them on the floor.

Result:
The items look like below and couldn't be picked up.



EDIT: I tried this again but used both the courier and a hero. Both give the same results.