Just got a bug today with Dota 2's UI, where if 2 people (person 1 and person 2) add each other via sending friend requests to each other (not using the accept button in the friends list), the person who sent the friend request after the other (person 2), won't appear on person 1's Dota 2 in-game friends list, meaning that they can't send gifts via Dota 2.
Person 2 can see person 1 fine however.

Can someone else test this to verify?