AWS Load Balancer has cross-zone load balancing disabled. This will prevent movement of traffic to registered targets outside the availability zone.
In AWS Console -
In Terraform -
References:
https://docs.aws.amazon.com/elasticloadbalancing/latest/application/load-balancer-subnets.html
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/lb#enable_cross_zone_load_balancing