Yes, the [@array] construct builds an array ref with a copy of the array --- But, the code in question uses the x operator to replicate a list of those references, and they will all be the same reference. Witness:

my @list = (3,2,1);
my @refs = ([@list]) x @list;
print "@refs\n";
__END__

which prints:

ARRAY(0x80f3764) ARRAY(0x80f3764) ARRAY(0x80f3764)
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Those are not references to the original array, they are all references to the same anonymous array that holds a copy of the original.