Movitdrive b losing program

I have a customer with a Movidrive B, that they have to reload the program after a power interruption. It has become quite a headache with the thunderstorms lately.

I haven't been on site yet, so I can't say for certain that it is losing all of the programs, but reloading the program (could be parameters or variables as well). Does solve the problem. They have replaced the individual drive a couple of times, and other drives around it are not effected. I believe that the parameters are updated via devicenet from the PLC for index lengths.

I haven't worked with the sew drives very much. And this sounds like an experience type problem. I'm trying to get as much info as possible, before going to the site tomorrow. Has anyone experienced something similar on Sew Eurdrives?

I do not think it's loosing the program since the fault is still there with the new drive. It could be something writing into the parameters via devicenet as you mentioned. May be P876 switched to off or something like that. Is the PLC writing into parameters or H variables? Could you save the parameter file (vdo) and email to me and let me know where the PLC is writing into the drive? I have pm you my email address.