Mode changing on its own to Away? (version 1 hub)

This morning I was rudely awakened around 5am when my alarm went off due to motion being detected. This was unexpected since motion is supposed to send alerts only when I am in away mode, and I was supposed to be in Home mode.

Looking at the history on my phone I saw that my mode had never been changed
from Home as far as the log was concerned but I was getting push and SMS messages as if I was Away. I confirmed that Smartthings thought I was away by using the phone app to set my mode to Home. The log then shows my mode changing from Away to Home, although the log never showed it being changed to Away in the first place; the last change in the log was to Home mode.

Is this a new bug? Anyone else been woken up in the middle of the night like this? Any suggestions for preventing future occurences?

I have not seen something like this happen. What I see is that the mode is changed, but the smart apps do not register any mode change, and hence fail to behave as per the expected mode. You might want to monitor for a few days and if you see it again definitely open a support ticket.

There were issues yesterday that smart things chose not to report to the community. See my thread.