Hello.
A friend of mine told me of one really strange issue with the playroom.
An account who was in his friends list simply disappeared, and he can't add this friend anymore, playroom is saying, unknown player.
The username of the account which simply disappeared is.
Jellygirl.
What's a cause of this problem?
This friend also told me, that same thing happened with other accounts.
Sorry for my very very bad english.
Regards

Hello,

It appears that she deleted her account recently (no more than a few days ago; it's currently scheduled for definitive removal).

You can of course no longer be friend with someone whose account don't exist anymore. That's why it disappeared from your list.