HS210 - Strange behavior

The HS210 3-way switch is installed on the circuit that controlls my front porch lights. I have the control set to come on at sunset and go off at 9:30 PM. That schedule has functioned flawlessly since the switch was installed.

Recently, I slept in the guest room due to an illness and sometime in the middle of the night, the front porch lights flashed on and off approximately five times. Since I was ill, I chalked it up to a fever dream... but the next night, the same behavior presented. I checked the clock and it was 5:08 AM.

Any ideas?