It's not normal and it's not something that should happen over multiple RB's. I guess normal applies, ensure latest ROS and FW. They may be applying config with safe mode on, losing connection and the board reverting changes.
I had the case with a customer, same symptoms. After some searches it appeared that the customer had made a configuration template, and then duplicated the config using "backup" and "restore" ! Which is not good for different devices, I told him to use export/import with .rsc files instead and his problems disappeared.