Route53 private hosted zone through terraform

Hi All, we are trying to create a route53 private hosted zone and create recordset to map load balancer. After we create the private hosted zone we try to associate another VPC to that private hosted zone. Below is the terraform code.

First terraform apply is working fine. But after that if we try to run terraform apply, terraform is trying to remove the secondary VPC id even though it is added as part of the terraform code.