Only if @array was declared outside the loop.</nit>

my @array;
for my $tab ( @things ) {
  @array = frobnicate( $tab );
  ## As you've seen, this leaves everything pointing at the same array
  $data{ $tab } = \@array;
}
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Were @array declared inside the loop you'd get a fresh instance each time through.

for my $tab ( @things ) {
  my @array = frobnicate( $tab );
  $data{ $tab } = \@array;
}
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