split takes a pattern as first argument, so your code doesn't do what you think. See split for details.

What you probably want is

my @Parts = split ' ', $Phrase;
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.

Update: Also, note the subtle difference between split / / and split ' '. The latter is "magical" in that it drops leading whitespace, splits on runs of spaces instead of a single space. The following may demonstrate:

my $s = '   a     b   c   ';

my @p = split ' ', $s;
print map { ">$_< " } @p;

my @q = split " ", $s;
print map { ">$_< " } @q;

my @r = split / /, $s;
print map { ">$_< " } @r;

my @s = split /\s+/, $s;
print map { ">$_< " } @s;

__END__
>a< >b< >c< 
>a< >b< >c< 
>< >< >< >a< >< >< >< >< >b< >< >< >c< 
>< >a< >b< >c<
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