Problem with DataPostProc addfeatures

[kktuax]

We are trying to plot a timeSeries NetCDF using geometries from an external GeoJSON as described in the documentation.

We have several layers in the NetCDF

netcdf spain-static_values-transposed {
dimensions:
	station = 8235 ;
	time = 1 ;
variables:
	string station(station) ;
		station:long_name = "station_name" ;
		station:cf_role = "timeseries_id" ;
	double lat(station, time) ;
		lat:_FillValue = NaN ;
		lat:units = "degrees_north" ;
		lat:long_name = "Latitude" ;
		lat:standard_name = "latitude" ;
	double lon(station, time) ;
		lon:_FillValue = NaN ;
		lon:units = "degrees_east" ;
		lon:long_name = "Longitude" ;
		lon:standard_name = "longitude" ;
	double fp_fd(station, time) ;
		fp_fd:units = "Number of days since year began" ;
		fp_fd:standard_name = "fp_fd" ;
		fp_fd:long_name = "Fisrt day of summer in first period" ;
		fp_fd:grid_mapping = "projection" ;
	int64 time(time) ;
		time:standard_name = "time" ;
		time:units = "days since 2021-06-07 00:00:00" ;
		time:calendar = "proleptic_gregorian" ;
	string projection ;
		projection:proj4 = "+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" ;

// global attributes:
		:featureType = "timeSeries" ;
		:Conventions = "CF-1.5" ;

We are able to plot the NetCDF with points and the Geometries independently, but once we combine them using the DataPostProc we get an error:

adagucserverEC/CAutoResource.cpp, 81 in CAutoResource] 2021-06-08T07:32:30Z Found dataset /tmp/adagucMgrCfg/summer-length-zoom-3.xml
adagucserverEC/CRequest.cpp, 822 in CRequest] 2021-06-08T07:32:30Z WMS GETMAP (0) first-period-last-day
adagucserverEC/CRequest.cpp, 1457 in CRequest] 2021-06-08T07:32:30Z Using maxquerylimit 365
adagucserverEC/CDataReader.cpp, 765 in CDataReader] 2021-06-08T07:32:30Z Working on [/data/summer-length/spain-static_values-transposed.nc]
adagucserverEC/CConvertADAGUCPoint.cpp, 113 in CConvertADAGUCPoint] 2021-06-08T07:32:30Z Using CConvertADAGUCPoint.h
adagucserverEC/CDataReader.cpp, 582 in CDataReader] 2021-06-08T07:32:30Z Assuming that for variable fp_ld the x dim equals x and the y dim equals y based on their position and name.
adagucserverEC/CDataReader.cpp, 609 in CDataReader] 2021-06-08T07:32:30Z Using variable x as X variable and variable y as Y variable.
adagucserverEC/CDataReader.cpp, 618 in CDataReader] 2021-06-08T07:32:30Z In level 2 compatibility mode, using a default stride of 1, not considering RenderSettings.
adagucserverEC/CDataPostProcessor.cpp, 1170 in CDPPAddFeatures] 2021-06-08T07:32:30Z CDATAPOSTPROCESSOR_RUNBEFOREREADING::Adding features from GEOJson
adagucserverEC/CDataPostProcessor.cpp, 1208 in CDPPAddFeatures] 2021-06-08T07:32:30Z Opening /data/summer-length/new-spain-zoom-3.geojson
adagucserverEC/CDataReader.cpp, 765 in CDataReader] 2021-06-08T07:32:30Z Working on [/data/summer-length/new-spain-zoom-3.geojson]
CCDFDataModel/CCDFGeoJSONIO.cpp, 36 in GeoJSONReader] 2021-06-08T07:32:30Z New CDFGeoJSONReader
adagucserverEC/CConvertGeoJSON.cpp, 520 in CConvertGeoJSON] 2021-06-08T07:32:30Z convertGeoJSONHeader
adagucserverEC/CConvertGeoJSON.cpp, 551 in CConvertGeoJSON] 2021-06-08T07:32:30Z addCDFInfo
adagucserverEC/CDataSource.h, 384 in CDataSource] 2021-06-08T07:32:30Z attachCDFObject: variable "fp_sl" does not exist
adagucserverEC/CDataReader.cpp, 790 in CDataReader] 2021-06-08T07:32:30Z Unable to attach CDFObject
adagucserverEC/CDataPostProcessor.cpp, 1214 in CDPPAddFeatures] 2021-06-08T07:32:30Z Can't open file /data/summer-length/new-spain-zoom-3.geojson
adagucserverEC/CDataPostProcessor.cpp, 782 in CDPPExecutor] 2021-06-08T07:32:30Z Processor addfeatures failed RUNAFTERREADING, statuscode 1
adagucserverEC/CImageDataWriter.cpp, 3375 in CImageDataWriter] 2021-06-08T07:32:30Z Error occured during image data writing
adagucserverEC/CRequest.cpp, 2215 in CRequest] 2021-06-08T07:32:30Z Returning from line 2078
adagucserverEC/CRequest.cpp, 3174 in CRequest] 2021-06-08T07:32:30Z WMS GetMap Request failed

<?xml version='1.0' encoding="ISO-8859-1" standalone="no" ?>
<!DOCTYPE ServiceExceptionReport SYSTEM "https://schemas.opengis.net/wms/1.1.1/exception_1_1_1.dtd">
<ServiceExceptionReport version="1.1.1">
  <ServiceException>
    attachCDFObject: variable "fp_sl" does not exist;
    Unable to attach CDFObject;
    Processor addfeatures failed RUNAFTERREADING, statuscode 1;
    Error occured during image data writing;
    Returning from line 2078;
    WMS GetMap Request failed;
  </ServiceException>
</ServiceExceptionReport>

We get always errors related to fp_sl layer even though we have requested other layers from the file. This is a snippet of our configuration:

<Configuration>
	<Legend name="summer-length-days" type="interval">
		<palette index="0" color="##ffffcc" />
		<palette index="30" color="#ffeda0" />
		<palette index="60" color="#fed976" />
		<palette index="90" color="#feb24c" />
		<palette index="120" color="#fd8d3c" />
		<palette index="150" color="#fc4e2a" />
		<palette index="180" color="#e31a1c" />
		<palette index="210" color="#bd0026" />
		<palette index="240" color="#800026" />
	</Legend>
	<Style name="summer-length">
		<Legend fixed="true" tickinterval="10">summer-length-days</Legend>
		<Min>30</Min>
		<Max>120</Max>
		<RenderMethod>nearest</RenderMethod>
		<NameMapping name="nearest" />
	</Style>
	<Style name="summer-length-last-day">
		<Legend fixed="true" tickinterval="10">summer-length-days</Legend>
		<Min>200</Min>
		<Max>300</Max>
		<RenderMethod>nearest</RenderMethod>
		<NameMapping name="nearest" />
	</Style>	
	<Layer type="database">
		<Name>first-period-summer-length</Name>
		<FilePath>/data/summer-length/spain-static_values-transposed.nc</FilePath>
		<DataPostProc algorithm="addfeatures" a="/data/summer-length/new-spain-zoom-3.geojson" />
		<Variable>fp_sl</Variable>
		<Styles>summer-length</Styles>
	</Layer>
	<Layer type="database">
		<Name>last-period-last-day</Name>
		<FilePath>/data/summer-length/spain-static_values-transposed.nc</FilePath>
		<DataPostProc algorithm="addfeatures" a="/data/summer-length/new-spain-zoom-3.geojson" />
		<Variable>lp_ld</Variable>
		<Styles>summer-length-last-day</Styles>
	</Layer>
</Configuration>

And the data files: summer-length.zip

Can you please advise? Many thanks in advance.