Address Override box ticking on Contacts - why?

I have a customer. The billing address does not have the 'override address' tick box ticked:

I create a new Contact:

I cannot edit the Address during the Create process:

When I save the Contact and then view it, the 'Override Address' option is ticked on the Contact Address:

Having the override box ticked is very dangerous as the users can think they have updated an address, but the actual address doesn't change:

How do I stop this happening? I have found an article that says I can update the 'Override' tick box via CSV import, but as far as I can tell I can't find this Override field in a Saved Search. So I would potentially have to update every single address in the system to ensure that these boxes are not ticked (which is not practical).