ダウンロードしたCSVは次のようになります。
これをexcelで開くと、最後の方の<font scolor=\"#444444\">から次の行の先頭に来てしまってます。
提示したのは短いコメントですが、たくさんHTMLを含むコメントにするとさらに見辛くなってしまいます。

"商品ID","規格ID","規格名1","規格名2","商品名","公開フラグ","商品ステータス","商品コード","通常価格","販売価格","在庫数","送料","ポイント付与率","購入制限","メーカーURL","検索ワード","一覧-メインコメント","一覧-メイン画像","詳細-メインコメント","詳細-メイン画像","詳細-メイン拡大画像 ","カラー比較画像","商品詳細ファイル ","詳細-サブタイトル（1）","詳細-サブコメント（1）","詳細-サブ画像（1）","詳細-サブ拡大画像（1）","詳細-サブタイトル（2）","詳細-サブコメント（2）","詳細-サブ画像（2）","詳細-サブ拡大画像（2）","詳細-サブタイトル（3）","詳細-サブコメント（3）","詳細-サブ画像（3）","詳細-サブ拡大画像（3）","詳細-サブタイトル（4）","詳細-サブコメント（4）","詳細-サブ画像（4）","詳細-サブ拡大画像（4）","詳細-サブタイトル（5）","詳細-サブコメント（5）","詳細-サブ画像（5）","詳細-サブ拡大画像（5）","発送日目安","おすすめ商品(1)","おすすめコメント(1)","おすすめ商品(2)","おすすめコメント(2)","おすすめ商品(3)","おすすめコメント(3)","おすすめ商品(4)","おすすめコメント(4)","おすすめ商品(5)","おすすめコメント(5)","おすすめ商品(6)","おすすめコメント(6)","カテゴリID"
"2","14","","","おなべ","1","11001","nabe-01","1700","1650","82","","5","5","","鍋,なべ,ナベ","<b>一人用からあります。</b>
<font size=\"+2\">てすと</font>","08311311_44f661811fec0.jpg","<b>たまには鍋でもどうでしょう。</b>
<font size=\"+2\">てすと</font>
<font scolor=\"#444444\">てすと</font>","08311313_44f661dc649fb.jpg","08311313_44f661e5698a6.jpg","","","","","","","","","","","","","","","","","","","","","","","3","","","","","","","","","","","","","4"