My current application is using M4 and is working fine.
I just ran a test on the current build from GitHub (RC2) and
encountered an error from the JSON.cfc conversion component.
Error Type: JSON.InvalidJSON : [N/A]
Error Messages: Invalid JSON
The document you are trying to decode is not in valid JSON format
The call was coming from the CookieStorage plugin at the following
143: <cfset rtnVar = instance.json.decode(rtnVar)>
Changing this to:
<cfif isJSON( rtnVar)>
<cfset rtnVar = instance.json.decode(rtnVar)>
fixes the problem.