[Client] Friends list randomly reorders itself

Normally the friends list sorts itself by status and then by alphabet, in the order 'online > in game > mobile chat app > away > offline' eg

D (online) B (in game) E (mobile app) C (away) A (offline)

Lately the friends list has been at random reordering itself into pure alphabetical order, ignoring friend status. eg

A (offline) B (in game) C (away) D (online) E (mobile app)

To recreate, open the client, pop up the friends list and wait I suppose. I could only guess at the reason for this, something to do with how long the client has been open for? Restarting the client puts the friends list back to normal... until it randomly reorders itself again.