The Intel XDK just had an update (v1912) correcting an issue where plugins were not installed correctly.. I will check to see it that is the problem.
Corrected the issue with intel.xdk plugins where if you selected the Emulator after selecting to include a plugin, the plugin was marked as "disabled" in the project.xdk file and thus was not included in the test or build uploads. In order for the plugins to work, you had to again deselect/select the plugin.
Corrected and issue where sometimes 3rd party plugins were not getting included in the built application.
Corrected an issue where if you selected the "Standard Cordova Plugins" check box (to select/deselect all Cordova plugins) then quickly selected/deselected individual plugins the list and build packages could get out of sync.