Can't purge existing file. Error: "path is invalid and does not exist on the site."

Setup/Background

Using .edgerc file to store credentials and is successfully authenticating

Configuration for Akamai

version: v3
disabled: false
storage_method: file
rest_api_url: 'https://akab-pf2w4w7pcnhgrack-pulmzmooht62g72e.luna.akamaiapis.net'
client_token: akamai
client_secret: akamai
access_token: akamai
edgerc_path: ../.edgerc
edgerc_section: xxxxx
basepath: 'https://xxx.xxx/'
timeout: 5
domain:
  production: true
  staging: false
action_v2:
  remove: true
  invalidate: false
action_v3:
  delete: true
  invalidate: false
log_requests: true
status_expire: 1209600
edge_cache_tag_header: true
purge_urls_with_hostname: null
edgescape_support: true
number_of_logs_to_delete: 20
_core:
edge_cache_tag_header_blacklist: {  }

Steps to Reproduce

• Navigate to: /admin/config/akamai/cache-clear
• Enter the path to a file that exists on the server: sites/default/files/somefile.pdf
• Click Start Refreshing Content

Things I noticed

• Entering a path to a node seems to work as expected. ie. node/1
• Under Akamai CCUV3 Settings there is an option to check: Purge URLs With Common Hostname. Checking doesn't save the selection.