Aurora 16 noise before powering up?

Hi, I'm a new owner of an Aurora 16. I have my Aurora hooked up to a power conditioner/distribution board in my rack, and power everything down overnight. I've noticed that when I turn on the power distribution board that services the Aurora 16 (amongst a bunch of other rack gear), the Aurora emits a loud relay noise from the rear of the unit (sounds kind of like a potato crisp bag being quickly scrunched up). This noise occurs BEFORE I actually turn the power button on at the Aurora 16 front panel. Is this normal when external power is first applied to the Aurora 16 (with the Aurora 16 itself being turned off at the front panel)? If so, it's my only piece of equipment that reacts in such a way to external power being applied, so just wanted to check if it is a 'normal' Lynx thing.

Steve