Hitting Rest Service asking to download response

I have a mock rest service that I have built using Grails. I am sending my response back with headers and in application/json format. For some reason when I use SoapUI to hit my endpoint I am getting my response perfectly, but then SoapUI is opening up a Save As window asking me to download the json response. When I hit our live rest servers I do not get this. I'm looking at the response from the live server and the response from my mock service application and they match. The only different I am noticing between the headers of the response from the live server and the mock server is that the headers are in a different order. Don't think that should make a difference.

For the life of me I can't figure out why SoapUI is asking to save the response. If I do save it then I get a popup that says the following:

Open [jar:file:///C:/Users/bmgriner/.JxBrowser/xulrunner-windows-version-1.9.1/xulrunner-windows/chrome/toolkit.jar!/content/mozapps/downloads/downloads.xul] with system Browser?

I've noticed that if I post to the rest url in Firefox hitting either the live endpoint or my mock service it asks me to download the content because Firefox doesn't know how to render the response. In IE it actually just renders the response showing me the json text.

Any ideas, hints as to what could be going on and how I can get rid of this Save As popup?