R and HDF5: reading a H5T_COMPOUND datatype with a nested H5T_ARRAY

I have an hdf5 file containing the following dataset:

 DATASET "data" {
     DATATYPE  H5T_COMPOUND {
        H5T_STD_U16LE "rlzi";
        H5T_STD_U32LE "sid";
        H5T_STD_U64LE "eid";
        H5T_ARRAY { [2] H5T_IEEE_F32LE } "gmv";
     }
     DATASPACE  SIMPLE { ( 39838472 ) / ( H5S_UNLIMITED ) }
     ATTRIBUTE "nbytes" {
        DATATYPE  H5T_STD_I64LE
        DATASPACE  SCALAR
     }
  }

Each record has an array "gmv" with two elements. I can read this dataset with the hdf5r package using the following code:

library(hdf5r)
fl <- h5file("file.hdf5", mode="r")
ds <- fl$open("/groupname/data")
dat <- ds$read()

Using this only reads one of the two "gmv" elements, to give a dataframe with the following structure:

'data.frame':   39838472 obs. of  4 variables:
 $ rlzi: int  26 11 13 14 1 2 5 14 14 11 ...
 $ sid : int  11 16 18 18 33 33 37 40 41 42 ...
 $ eid :integer64 322350180466688 322350180466688 322350180466688 ...
 $ gmv : num  0 0 0 0 0 0 0 0 0 0 ...

Is there any way I can read both elements of the gmv array for each record?