In GeoServer, if a layer is a view or does not have a primary key, the resulting "fid" is not unique.
"fid" is used by the FeatureGrid to refer features to be exported (csv, shp, or other formats), so in this case it will try to filter the one-time-use "fid" of the loaded features, resulting in an empty export.
In GeoServer, if a layer is a view or does not have a primary key, the resulting "fid" is not unique. "fid" is used by the FeatureGrid to refer features to be exported (csv, shp, or other formats), so in this case it will try to filter the one-time-use "fid" of the loaded features, resulting in an empty export.