Conditionally create resources when a for_each loop is involved

I tried terrform import with some trouble.

Terraform import aws_instance force replacement for network_interface

I added count to an aws_instance (e.g. bastionaws1) to allow conditional creation, so I need to terraform import new bastionaws1[0] linked resources and remove old ones (basrionaws1). I correctly imported aws_instance, the instance has attached ENI so I also imported resource network_interface. On terraform plan I get that instance will be replaced becouse network_interface force replacement:

 # module.bastionaws1[0].aws_instance.this must be replaced
-/+ resource "aws_instance" "this" {
   ...
     + network_interface { # forces replacement
         + delete_on_termination = false
         + device_index          = 0
         + network_interface_id  = "eni-..."
       }

Not tried terraform state mv yet but probably I’ll get same result.