It didn't update for me at 16:00 (UTC) as well. It usually means that no block was found by the pool between 15:00 and 16:00. It should update at 17:00, if the pool finds a block within the next 48 minutes (or has found a block within the last 12 minutes).
No, this time the balance was not updated because of a bug in the software.
Thanks for pointing this out, we are working to fix updating, please wait.