Every time I have a momentary power failure, my VeraPlus, turns on the outside lights. The lights are scheduled for sunset come on with a fixed time off.
You might want to give more details about your lights. What are they? Make and model number etc.
Maybe there is a device setting for power restored behaviour? Read the user manual for the “lights”.
Lights are LED outdoor units that are controlled by GE ON/off z wave switches. I use the switches for inside lights, as well. The inside lights never come on during a momentary power hit. Also, the inside lights are not scheduled like the outside lights.