runtime.executionContext and Map/Reduce

I want to be able to detect where the script triggered from so that I can ignore some script parameters. I am using runtime.executionContext which according to the doc returns a runtime.ContextType that represents what triggered the current script. When I log out the runtime.executionContext in my Map/Reduce, i get "MAPREDUCE". This isn't even in the runtime.ContextType object (see below for object details). Is there an issue with this currently? Is there something else I should be using to detect if my map/reduce was triggered from the user interface?

runtime.ContextType log:

  {     "USER_INTERFACE":"USERINTERFACE",     "WEBSERVICES":"WEBSERVICES",     "WEBSTORE":"WEBSTORE",     "PORTLET":"PORTLET",     "SCHEDULED":"SCHEDULED",     "SUITELET":"SUITELET",     "CSV_IMPORT":"CSVIMPORT",     "CUSTOM_MASSUPDATE":"CUSTOMMASSUPDATE",     "WORKFLOW":"WORKFLOW",     "USEREVENT":"USEREVENT",     "ACTION":"ACTION",     "DEBUGGER":"DEBUGGER",     "CLIENT":"CLIENT",     "BUNDLE_INSTALLATION":"BUNDLE_INSTALLATION",     "RESTLET":"RESTLET",     "WEBAPPLICATION":"WEBAPPLICATION",     "PAYMENTGATEWAY":"PAYMENTGATEWAY",     "CONSOLRATEADJUSTOR":"CONSOLRATEADJUSTOR",     "PROMOTIONS":"PROMOTIONS",     "CUSTOMGLLINES":"CUSTOMGLLINES",     "TAX_CALCULATION":"TAXCALCULATION",     "SHIPPING_PARTNERS":"SHIPPINGPARTNERS",     "EMAIL_CAPTURE":"EMAILCAPTURE"  }