Terraform 0.7.11 Experimental Feature Error on aws_instance resource

terraform-0.7.11-experimental-feature-bug

While running, Terraform sometimes tests experimental features in the 
background. These features cannot affect real state and never touch
real infrastructure. If the features work properly, you see nothing.
If the features fail, this message appears.

The following failures happened while running experimental features.
Please report a Terraform bug so that future Terraform versions that
enable these features can be improved!

You can report an issue at: https://github.com/hashicorp/terraform/issues

2 error(s) occurred:

* apply operation: Unknown 'ValidateResource' shadow value for "aws_instance": &errors.errorString{s:"shadow closed"}
* apply operation: Diff "aws_instance.artifactory" had unequal states (real, then shadow):

&terraform.ResourceConfig{ComputedKeys:[]string(nil), Raw:map[string]interface {}{"associate_public_ip_address":"true", "tags":[]map[string]interface {}{map[string]interface {}{"Name":"TF - MANAGEMENT - Artifactory"}}, "root_block_device":[]map[string]interface {}{map[string]interface {}{"volume_type":"standard", "volume_size":8, "delete_on_termination":true}}, "user_data":"${file(\"./data/init_artifactory.sh\")}", "availability_zone":"${var.artifactory_az}", "key_name":"${aws_key_pair.access-key.key_name}", "vpc_security_group_ids":[]interface {}{"${aws_security_group.artifactory.id}"}, "subnet_id":"${aws_subnet.zone-a.id}", "ami":"${var.artifactory_instance_ami}", "instance_type":"${var.artifactory_instance_type}"}, Config:map[string]interface {}{"tags":[]map[string]interface {}{map[string]interface {}{"Name":"TF - MANAGEMENT - Artifactory"}}, "instance_type":"t2.medium", "subnet_id":"<xxx>", "ami":"ami-8504fdea", "vpc_security_group_ids":[]interface {}{"<xxx>"}, "associate_public_ip_address":"true", "availability_zone":"eu-central-1a", "key_name":"management-key", "user_data":"#!/bin/bash\n\n### Install Artifactory\necho \"deb https://jfrog.bintray.com/artifactory-debs xenial main\" > /etc/apt/sources.list.d/artifactory.list\ncurl https://bintray.com/user/downloadSubjectPublicKey?username=jfrog | sudo apt-key add -\nsudo apt-get update\nsudo apt-get install -y openjdk-8-jre-headless\nsudo apt-get install -y jfrog-artifactory-oss\n\n", "root_block_device":[]map[string]interface {}{map[string]interface {}{"volume_type":"standard", "volume_size":8, "delete_on_termination":true}}}, raw:(*config.RawConfig)(0xc4200e7500)}

&terraform.ResourceConfig{ComputedKeys:[]string(nil), Raw:map[string]interface {}{"availability_zone":"${var.artifactory_az}", "subnet_id":"${aws_subnet.zone-a.id}", "ami":"${var.artifactory_instance_ami}", "user_data":"${file(\"./data/init_artifactory.sh\")}", "root_block_device":[]map[string]interface {}{map[string]interface {}{"volume_type":"standard", "volume_size":8, "delete_on_termination":true}}, "instance_type":"${var.artifactory_instance_type}", "associate_public_ip_address":"true", "key_name":"${aws_key_pair.access-key.key_name}", "vpc_security_group_ids":[]interface {}{"${aws_security_group.artifactory.id}"}, "tags":[]map[string]interface {}{map[string]interface {}{"Name":"TF - MANAGEMENT - Artifactory"}}}, Config:map[string]interface {}{"subnet_id":"subnet-5d3e8035", "user_data":"#!/bin/bash\n\n### Install Artifactory\necho \"deb https://jfrog.bintray.com/artifactory-debs xenial main\" > /etc/apt/sources.list.d/artifactory.list\ncurl https://bintray.com/user/downloadSubjectPublicKey?username=jfrog | sudo apt-key add -\nsudo apt-get update\nsudo apt-get install -y openjdk-8-jre-headless jfrog-artifactory-oss\n\n### Configure Artifactory\necho \"JAVA_OPTIONS=\\\"-server -Xms512m -Xmx2g -Xss256k -XX:+UseG1GC\\\"\" > /etc/opt/jfrog/artifactory/default\n", "tags":[]map[string]interface {}{map[string]interface {}{"Name":"TF - MANAGEMENT - Artifactory"}}, "availability_zone":"eu-central-1a", "associate_public_ip_address":"true", "root_block_device":[]map[string]interface {}{map[string]interface {}{"delete_on_termination":true, "volume_type":"standard", "volume_size":8}}, "instance_type":"t2.medium", "key_name":"management-key", "vpc_security_group_ids":[]interface {}{"<xxx>"}, "ami":"ami-8504fdea"}, raw:(*config.RawConfig)(0xc4203ad5c0)}

This is not an error. Your terraform operation completed successfully
and your real infrastructure is unaffected by this message.