You aren't really treating them the same by localizing the input record separator:

my $data = do { local $/; <RI> }; # or however you load it.

Instead try this:

  @data = <RI>;
  chomp(@data);
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or

  while ($line = <RI>) {
    chomp $line;
    ...
  }
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Then cycle through the data list. This is what you do in your array example.

I suppose that answer is a bit backwards, however. Once you get the data in list format, you no longer need the split that you were using due to having overridden the input record separator:

for ( split /\n(?=\S)/, $line )
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Instead just use:

for my $line (@lines) {
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Matt