message: isHtml makes no sense if there is no formatted_body
  this is a bug pre-replies but replies exacerbates it
diff: @@ -414,7 +414,7 @@ class TextHighlighter extends BaseHighlighter {
  * opts.stripReplyFallback: optional argument specifying the event is a reply and so fallback needs removing
  */
  export function bodyToHtml(content, highlights, opts={}) {
  - const isHtml = (content.format === "org.matrix.custom.html");
  + const isHtml = (content.format === "org.matrix.custom.html") && content.formatted_body;
  let body;
  if (isHtml) {
  body = content.formatted_body;
  