That’s why it catches people out. Most people (including me) would not expect a device to behave like that, but the model series appears to be deliberately designed that way.
There may be other things affecting the case when (I think ?) you said that no power outage was involve. There might be a special edge case (like maybe if you save the patterns but the project itself is not saved perhaps ?) but the power loss will definitely account for some of your troubles.
There are others who have had the same experience. This is a quote from just one thread