Passing a node field as a contextual filter to a view pane
I found a straightforward solution for this in a comment in the issue queues:


  Basically there is a Display Mode on each content type for Tokens that can be used to control exactly what is rendered by tokens that are used.
  
  To enable it per content type, do the following:
  
  
  In the actual Content Type itself, got to the "Manage Display" tab.
  Scroll down to the end of the field listing and click the "Custom Display Settings" link.
  Enable (Check) and Save the Token option to enable the Token Display mode.
  Go to that display mode (Grey display mode tabs near the top) and any field settings you do here effect what the tokens render (which is the same ones Panels uses).