undef does not work the way you think it does:

      if(undef($text)) { ...
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This will always set a variable to undef. You likely want defined as in if( ! defined($text)) { ...:

foreach my $row (@{$data_all})
{
    say $row;
    my %currec = %{$row};
    foreach my $columns (keys %currec) {
      my $text = $currec{$columns};
      say $text;
      if(! defined ($text))
      {
        say "$columns is NOT DEFINED";
      }
      elsif (length($text) < 1)
      {
        say "$columns DEFINED, but empty";
      }
    }
    exit;

}
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