Here's a non-aliasing version that does work, but it doesn't perform very well. Why it works is left as an exercise.

sub bukNoAlias (@) {
    my @a = @_;
    my( $n, $t );
    my $i = @_;
    map+( $t=$a[ $n=rand($i--) ], $a[ $n ]=$a[ $i ] )[ 0 ], @_;
}
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