qw() does not return an array, it returns a list:

$x = {
  foo => 'bar',
  baz => qw( bax bof )
}
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is equivalent to

$x = {
  foo => 'bar',
  baz => 'bax', 'bof'
}
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And that should give you a "odd number of elements" warning if you have warnings enabled.

You can do

$x = {
  foo => 'bar',
  baz => [ qw( bax bof ) ]
}
[download]

to transform the list into an anonymous array and all will be fine.

Update: removed nonsense new() calls.