You’ll definitely see some wonky friends list issues while the account migrations are taking place. The way they work is that when someone logs on during 4.5, their account automatically sends requests to everyone they previously had on their list. When someone on their list logs on, they will likewise send a batch request, and will automatically accept any batch requests sent to them. Ideally, this is all invisible, and players won’t know the difference, but I imagine there are lots of little things that can go wrong and make the friends list behave strangely.
It’s not just that, you can’t also deny a friend request. I click, it vanish and after one game or quit/open the game again - that same request is there.