since you don’t seem to have had a pre-existing relationship with the raven, i assume the bone hitting you was just coincidence. but then again, maybe it wanted to give you a gift? or maybe it wanted to play with you? or maybe you startled the raven as you walked past the tree? did you see the raven go get the bone again after you left?
i’ve seen gulls play games where they pick up a fish, fly a short distance, and drop it for another to gull pick up, and i’ve seen cases where other birds intrude into the game and take the fish away. the gulls look at the other bird as if to say that other bird doesn’t play the game right.