Need help with Syntax for sourceImage

In our Packer properties.json file we’re currently searching for a specific AMI to base our AMI builds off of. These are looked up and set during codebuild in pre-build. The code we’re using is below: SOURCE_IMAGE, SOURCE_OWNER, and SET_TAG get replaced by code running in pre_build.

I know they are set correctly, however the tag:Route filter doesn’t seem to be working. During my build I’m setting that variable to “stable” however it doesn’t appear to be working since the AMI it used had a tag of “unstable”

I was hoping someone could let me know if I have the syntax wrong. The tag name is ‘Route’

If more info is needed I’ll see what I can post, however I appreciate any help on this.

  "username": "Administrator",
  "sourceImage": {
    "filters": {
      "virtualization-type": "hvm",
      "name": "SOURCE_IMAGE",
      "tag:Route": "SET_ROUTE",
      "root-device-type": "ebs"
    "owners": [
    "most_recent": true