Thanks for the report about this. This is something we are still looking into, and if you happen to notice this issue occurring in your Diablo III game client, could you perhaps give us a rundown of what happened prior to this occurring?
When did you encounter this (day/time)?
Had you recently been disconnected from the internet while playing Diablo III?
Had your game client been open for a significant period of time? Were you auto-disconnected due to inactivity?
Do you use the Battle.net Desktop Application to launch Diablo III, or do you bypass the launcher(s)?
Did you attempt to log in and fail (either from typing the wrong info, or from being disconnected from the internet)?
Any other information you can provide about what led to you encountering this would be appreciated. Thanks!