TDS 5.0 NCSS missing projection info

[dopplershift]

NCSS returns from TDS 5.0 are missing the grid_mapping attribute on data variables and the projection variable. This query:

https://thredds-test.unidata.ucar.edu/thredds/ncss/grid/casestudies/irma/model/gfs/Best?var=Geopotential_height_isobaric&time_start=2017-09-05T00%3A00%3A00&time_end=2017-09-08T00%3A00%3A00&west=-120&east=-50&south=15&north=55&accept=netcdf4&vertCoord=50000

Yields a netCDF file with the following CDL:

netcdf temp {
dimensions:
	time1 = 25 ;
	latitude = 81 ;
	isobaric3 = 1 ;
	longitude = 141 ;
variables:
	double time1(time1) ;
		time1:units = "Hour since 2017-09-01T00:00:00Z" ;
		time1:standard_name = "time" ;
		time1:long_name = "GRIB forecast or observation time" ;
		time1:calendar = "proleptic_gregorian" ;
	float latitude(latitude) ;
		latitude:units = "degrees_north" ;
		latitude:standard_name = "latitude" ;
	double isobaric3(isobaric3) ;
		isobaric3:units = "Pa" ;
		isobaric3:positive = "down" ;
	double reftime1(time1) ;
		reftime1:units = "Hour since 2017-09-01T00:00:00Z" ;
		reftime1:standard_name = "forecast_reference_time" ;
		reftime1:long_name = "GRIB reference time" ;
		reftime1:calendar = "proleptic_gregorian" ;
	float longitude(longitude) ;
		longitude:units = "degrees_east" ;
		longitude:standard_name = "longitude" ;
	float Geopotential_height_isobaric(time1, isobaric3, latitude, longitude) ;
		Geopotential_height_isobaric:long_name = "Geopotential height @ Isobaric surface" ;
		Geopotential_height_isobaric:units = "gpm" ;
		Geopotential_height_isobaric:Grib_Variable_Id = "VAR_7-0--1-5_L100" ;
		Geopotential_height_isobaric:Grib2_Parameter = 0, 3, 5 ;
		Geopotential_height_isobaric:Grib2_Parameter_Discipline = "Meteorological products" ;
		Geopotential_height_isobaric:Grib2_Parameter_Category = "Mass" ;
		Geopotential_height_isobaric:Grib2_Parameter_Name = "Geopotential height" ;
		Geopotential_height_isobaric:Grib2_Level_Type = 100 ;
		Geopotential_height_isobaric:Grib2_Level_Desc = "Isobaric surface" ;
		Geopotential_height_isobaric:Grib2_Generating_Process_Type = "Forecast" ;
		Geopotential_height_isobaric:coordinates = "reftime1 time1 isobaric3 latitude longitude " ;

// global attributes:
		:Originating_or_generating_Center = "US National Weather Service, National Centres for Environmental Prediction (NCEP)" ;
		:Originating_or_generating_Subcenter = "0" ;
		:GRIB_table_version = "2,1" ;
		:Type_of_generating_process = "Forecast" ;
		:Analysis_or_forecast_generating_process_identifier_defined_by_originating_centre = "Analysis from GFS (Global Forecast System)" ;
		:Conventions = "CF-1.6" ;
		:history = "Read using CDM IOSP GribCollection v3" ;
		:featureType = "GRID" ;
		:History = "Translated to CF-1.0 Conventions by Netcdf-Java CDM (CFGridCoverageWriter)\nOriginal Dataset = irma-GFS-Global_0p5deg#Best; Translation Date = 2017-11-08T23:48:56.887Z" ;
		:geospatial_lat_min = 14.75 ;
		:geospatial_lat_max = 55.25 ;
		:geospatial_lon_min = -120.25 ;
		:geospatial_lon_max = -49.75 ;
}

Note the distinct lack of any projection information.