This has happened several times:

I have added a user as a friend.
That user has also added me as a friend.
There is a clear record of that in the private messages.

However, when I go to that users page OR click on a private upload that has been sent to me, I still see the following message "Some of the pics may be invisible because they are for members/friends only"

Similarly, I am friends with another user (and vice versa) but can only see their two public pics, when it clearly says that this user has 90.

Any advice as to how to remedy this?