Is there something wrong with my 3TB fusion drive?

Hi:

I have been unable to restore my 3 TB fusion drive from my Time Capsule backup in El Capitan. I keep getting the error message can't erase the disk.

I am also not able to erase the drive without having to go through multiple steps using terminal.

Is this normal behavior for a fusion drive when using El Capitan? Or is there actually something wrong with my hard drive?

The techs at the Genius Bar tell me that this is normal behavior which contradicts what I am hearing from a senior advisor.

Who is right the techs at the Genius Bar or the senior advisor?

Thanks

Dave