I have had SIGNIFICANT issues with this problem. I have over 75 Insteon devices in my automated home and the EZIO2X4 is the ONLY device that continually loses its NVRAM contents. After about 1/2 of the power failures we experience, I have to go back into the EZIO and reset its links and the CMMD1/CMMD2 Insteon messages sent on input transitions.
This has been going on for several years. I just sent my unit back to SmartenIt to have it checked and a new PLM installed.
Hopefully it will make a difference.