don't see the error offhand yet, but do have some code comments/suggestions after a qiuck read..

  use strict;    # use em if
  use warnings;  #   you're not already

  my @loop;

  # first, prepare the SQL .. this can be more efficient.
  # BUT more importantly, this also is using placeholders
  # ALSO note the column aliases .. this makes things more convenient 
+below.
  my $sth = $dbh->prepare("SELECT item1 as _first_item, item2 as _seco
+nd_item, item3 as _third_item FROM table WHERE topic = ? ORDER BY id 
+ASC");

  # no need for a $y index ..
  foreach my $topic ( @topic[0 .. $x-1] ){  # just use an array slice 
+to get the topics
    $sth->execute( $topic );    # passing a value to the placeholder
    push @loop, {
      _TOPIC => $topic,
      _ITEMS => $sth->fetchall_arrayref({}),   # use a DBI function to
+ get the AoH of items
    };
  }

  $html->param(_TOPICS => \@loop);
  $html->output;
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Hopefully clearing up the code i little w/some of those suggestions will make the bug more apparent ..

Can you also post the template source that your code is using?


update: can further simplify to a map statment:

  my $sth = $dbh->prepare("SELECT item1 as _first_item, item2 as _seco
+nd_item, item3 as _third_item FROM table WHERE topic = ? ORDER BY id 
+ASC");
  my @loop = map {
    $sth->execute( $_ );
    {  _TOPIC => $_,  _ITEMS => $sth->fetchall_arrayref({})  };
  } @topic[0 .. $x-1];
[download]