GRIB messages whose packingType is "grid_complex_spatial_differencing" are not fully supported in Metview computations. Therefore it is recommended to convert this data into "grid_simple" packing. This can done in Metview from version 5.17.0 using grib_set:
f = mv.grib_set(f, ["packingType", "grid_simple"], repack=True)
In older Metview versions the repack option is not available, so the same conversion has to be done outside Metview using ecCodes command line tools (see here).