Unfortunately, you lose data if you dump AoH or AoA structures. Try this structure as a test case:

my %hash = ( b => [ {x => 1, a => 2, z => 3},
                    {1 => 'x', 2 => 'a', 3 => 'z'},
                  ],
             a => [ [0,1],[1,1],[-1,1],[-1,-1] ],
            );
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