[@robkk Moderator 10 years, 1 month ago]

This issue is caused because the widget links have the same classes as other links throughout bbPress. In your theme mesocolumn, there is CSS in a bb-css stylesheet that bolds the forum titles.

In this custom CSS I just set a default font-weight for any widget area.

You may need to show your theme author this so that maybe they can add it or something similar to their theme.

And I need to note this down as a possible issue that users might occur when customizing their forums/developing themes.

This is custom CSS add it in the custom css area your theme provides.

.widget-area li a {
  font-weight: normal;
}