If my SB is in Sleep for over a couple hours and it is plugged in to the charger it will crash with the same error reported as you are getting. If it is in Sleep on the battery (not plugged in to the charger) it will not crash and will exit sleep normally with the desktop preserved. If I enable Hibernate (default setting - SB enters Hibernate after two hours) and the SB is not connected to the charger it will come out of Hibernate normally, with the desktop preserved. If the SB is plugged in to the charger and it Hibernates it usually doesn't crash but the Hello camera will fail to operate when it comes out of Hibernate until I restart the SB.
Check your settings. If your SB is set to Sleep only and you are leaving it plugged in to the charger, then you are likely experiencing the same issue that I am having. My temporary workaround is to set the Sleep settings to "Never" when Plugged In. All other settings are left to the default. Therefore my SB does not enter Sleep (or Hibernate) when plugged in. So far (five days now) it has not crashed when plugged in or on battery.
This is a widely reported issue and I remain hopeful that Microsoft will release an update that addresses this issue.