RSS feed currently broken by illegal PCDATA chars in a post

The illegal chars can be found in the post "Glyph Lefkowitz: iOS Mail To Omnifocus Task":

<li>Continue holding down with your first finger.  With a <em>second</em> finger, swipe
  | up from the bottom to enter the multitasking view, or to go back to your
  | home screen.  While holding your first finger in place, either switch to or
  | launch OmniFocus.</li>

The char after "view" is causing the issue.

A simple measure would be replacing such control chars with empty strings.

まず、リンクされた投稿の RSS feed 生成パスを特定し、「view」の後に示されている制御文字を使って feed の失敗を再現します。RSS feed が有効になり、問題の制御文字が周囲の内容を変更せずに削除または除外されれば完了です。